Softrock Lite 6.2
Adventures in Electronics and Radio
Elecraft K2 and K3 Transceivers
November 2006 Archive
30 November 2006
I've made some progress with the "CX" graphic LCD
controller boards. The photo below shows the introduction screen as seen on a
Crystalfontz CFAG320240CX-TFH-T# display.
This model display is a "transreflectance" version,
showing black characters on a light background, with the advantage that the
characters may be read whether the backlight is on (transmission mode) or off
(reflectance mode). The disadvantage of this format, in my opinion, is that it
is not particularly legible in either transmission or reflectance mode. A major
plus of this particular display model is that it is available with a touch
screen overlay, which, it it had been available a year ago when I started the
Z90, I would have used instead of the six soft key hardware switches.
Fortunately, the CX controller board is fitted to several
different display types, including a blue/white CCFL version identical to the
current Z90 display. However, the touch screen overlay is only offered by
Crystalfontz as part of the transreflectance display.
Splash Screen as seen on a "CX" controller with the
S1D13700 controller, with an experimental version of the Swordfish S1D13700
My plan is to fill all current orders with "C0" blue/white displays, from my
current stock of displays. I will continue to develop the CX firmware, however,
with the thought that should there be sufficient interest in a second kit run,
it would use the CX display controller.
I might shift to touch screen control, which has certain
advantages, although it would require reworking the PCB layout. (The LED
backlighting also will require reworking the PCB, but there's plenty of room for
those revisions in the CCFL inverter area.) My main concern is whether the
transreflectance display has sufficient visibility. I'll build up one or two
CX-Z90's and see how they work for me, and perhaps circulate them to a few Z90
customers to solicit their views as well. That's a project not likely to be
underway until next year, however. And, actually carrying it through to another
run of kits depends on the continued interest the Z90. Based on my experience
with the current Z90 & Z91 run, a future kit build will only be for the Z90
version and will require a minimum order commitment of 40 to 50 customers.
29 November 2006
I inadvertently tested the polyfuse today. I've been
working on revising the Z90 firmware to use the newest design LCD modules with a
S1D13700 controller. To do this, I've been using a Z90 PCB laying open on my
desktop, with a soft key board plugged into it, and the display propped against
This evening, the PCB stopped working. Checking the
voltage levels, I found the +12V supply was dragged down to a fraction of a volt
and the polyfuse was very hot to the touch. After checking a few simple things,
I found that the coaxial jumper between W201/202 and W101/102 was shorting the
+12V line. A short but sharp bypass capacitor lead pierced the coax jumper's
jacket and applied a dead short circuit to the +12V line.
Don't let this happen to you when testing your Z90.
27 November 2006
I've posted a new Z90/91 firmware release, version 606, at
the Software page. It makes the following changes:
- Revised the Z90's softkey delay procedures for Custom IF, Custom Span and
Generate Frequency to make it easier to select digits and set their values.
Earlier releases tended to advance a digit as soon as you released the switch.
The behavior is much more user friendly in version 606.
- Changed the vertical position automatic repeat to 5 dB/step. Earlier
versions increased the vertical trace position in 1 dB steps, changing to 10
dB steps if the soft key were held in for an extended time. The large scale
step is now 5 dB instead of 10 dB.
- The software version is sent over the RS232 line at power up.
I recommend that Z90 users install the update, but Z91 users may wish to skip
A good part of yesterday and today were consumed by
cleaning out the garage. Northern Virginia is an area of active termites, and
the initial ground treatment when our house was built 20 years ago has
dissipated and a new application is to be made tomorrow. Part of the treatment
is to inject the anti-termite liquid into the ground around the garage's
foundation, via a series of holes drilled through the floor around the
perimeter. This means moving all the shelving and their contents from around the
walls to the center of the garage. Although I threw out quite a bit of "stuff"
there was still a lot to move. Then, we get to move it back on Wednesday, after
25 November 2006
Glenn, VK4TZL, has provided a photo of his Z91 sitting
next to one of his K2s. I've posted the photo and his comments on the Z91 at the
User Views page. Glenn also provided photos of his
Z10000-K2 buffer amplifier installation and I'll post those as well on the
Construction Updates page.
I've had a question about the odd odor from the panels. I
believe this is from the protective film, and it will dissipate after a few days
use. Or, you could lay the panels outside to air out while you are building the
Today's E-mail also brought a few questions about the Z90.
I've added the questions, and answers, to the FAQ page.
The questions are:
- Why does the BFO leakage signal shift when the K2 mode
is changed from USB to LSB and vice versa?
- Why can't I generate a signal above 60 MHz from the
Z90's auxiliary signal output port?
I also had a request to modify the way the signal
generator, custom IF and custom span, soft keys work. In particular, in the
current software release, it can be difficult to set a value using the automatic
repeat function, as when you stop pressing the button, the value continues to
advance one step. I've reworked the automatic repeat delay function and
corrected this behavior. As soon as I receive feedback from the requestor on the
test firmware, I will make it available for general use. To some extent, the
vertical position soft key suffers from a similar problem when it advances into
the 10 dB/step mode. Unfortunately, this behavior is not likely to be altered
soon, as it would require major reworking of the interaction between the screen
display and button reading.
24 November 2006
I finished both Z90 PCBs this afternoon and ran through a
checkout. One board checks out perfectly, but the second has a problem with the
1 KHz bandpass filter. I suspect that I exchanged two capacitors when stuffing
the PCB as the response has a dip in the passband. Or, I might have damaged one
of the crystals by overheating when soldering the third wire to it. I'll dig
into it tomorrow.
I didn't keep track of the exact build time, but I think
it was about 16 hours total for two PCBs, no cabinet installation. There's only
a modest time savings from building two boards in parallel. I used K7HBG's
suggestion for finishing the coaxial jumper shields, wrapping them with small
diameter bare wire, and it produces a nicer looking finish.
Stan, W5EWA, in an E-mail message to me, reminded himself
of the benefits of the Z10010 4915 KHz bandpass filter provided with Z90/91's to
be used with K2 transceivers. Here's his message:
Jack, I was experiencing some baseband lifting this
morning on 20m. It was up 20 to 25dB at times. I thought I had something wrong
with the Z90. I had everything disconnected while upgrading the K2 and hooking
up the XV units. I was sure I had everything hooked up properly, and was
puzzled as to what was going on. I finally looked around at the back of the
Z90 and when I THOUGHT that I had hooked up the IF filter (Z10010), I actually
had not. I had taken the short jumper that you provided and had it connected
across the two connectors on the Z10010. Bottom line is, that when I hooked up
the Z10010 everything started looking normal. It took the baseband down from
20dB to around 5dB or less. So it DOES work. I'm glad that happened. It gave
me a real chance to see what the filter is capable of.
The Z90's dynamic range is about 60 dB, which is
reasonably for a broadband device with four inexpensive crystals as the only IF
filtering. However, the K2, as with most receivers, has a much greater dynamic
range. When very strong signals are present within the K2's passband, an
displacement of the Z90's baseband line (shift upward) is seen. The K2's
passband is on the order of 1 MHz, so the strong broadcast band signals in the
13 MHz band will be passed along to the Z90's input when tuning the 20 meter
band, as Stan was doing. The Z10010 filter knocks down these out-of-band signals
by 20 to 30 dB and thus significantly improves the Z90's dynamic range. The
Z10010 won't do anything for strong in-band signals, and judicious use of the
Z90's attenuators and the K2's RF Preamp/Attenuator will be beneficial.
23 November 2006
Matt, KC0UKK, reports his Z90 is finished and provided a
screen shot of a test signal, along with a question. See the
Construction Updates page for the image
and my answer.
I started building two Z90s for my own use yesterday and
have one completed through Stage 6 and the other through Stage 5. I thought that
after building six Z90's in various designs, that I didn't need the Assembly
Manual. Wrong. I started before lunch yesterday and wanted to knock out a quick
module before breaking for lunch, so I built two soft key boards. Well,
actually, I built three soft key boards because I put the 10-pin connector on
the wrong side of one of the boards. It was easier to scrap that board and build
a new one than to try and get the connector off without pulling the through-hole
plating out, even with solder wick and a Weller vacuum de-soldering station.
I also followed Matt's suggestion on crystal grounding and
I've posted a photograph of his "three pin" crystal modification on the
Construction Update page. I like it;
seven out of the eight crystals have a ground via centered and those work well
with the modification. The eighth crystal has a nearby via that can be used for
grounding. I doubt this makes any improvement in performance, but it's a cleaner
22 November 2006
Oops ... the Z90 firmware update 604 I posted earlier this morning has a
problem, in that it requires the LCD Display to be attached in order to run, and
hence fails when run on a Z91. I've deleted it from the Software page and if you
installed it, please install version 605 now available at the
Software page, which runs correctly on either a Z90
I've posted a Z90 (and also Z91) firmware update, version 605, to the
Software page. Version 605 makes two changes to the
- Decreases the time between power-on and the five second count-down
sequence from 1 second to 200 milliseconds. This will reduce the annoying
screen flash when powering up the Z90.
- Displays the firmware release number during the five second count-down
If you download version 605, it is not necessary to also install EEPROM data
and accordingly re-calibrating your Z90 will not be necessary.
22 November 2006
Matt, KC0UKK reports his Z90 is completed and operating,
and I've added his comments, along with those from Glenn, VK4TZL, to the
User Views page.
I've also added the following message to the Delivery
Updates part of this page:
I've completed an inventory of the kit packages on hand, and orders to
be delivered. It looks as if I will have the ability to deliver a few more
Z90 or Z91's from my reserve. Since the reserve is intended, in part, to
support lost or damaged shipments, or missing stage bags, I will not
release these reserves until after all current orders are delivered, an
event that I expect to occur around the end of 2006.
The reserve looks to permit delivery of five additional Z90's or Z91,
or any mix of the two that adds up to five. I will have to order some
additional, expensive, parts to meet these orders, primarily Z90
enclosures and LCD modules, as I purchased those items with only one or
I may, and emphasize, may, have two or three Z10000 buffer
amplifiers to go along with these Z90/91's. I did not expect to sell two
or three buffer amplifiers with each Z90 and hence the buffer amplifiers
do not have a similar reserve stock.
I will meet these orders in order
of date received, so if you are interested in a Z90 or Z91, please send me
an E-mail message with your order information at the address at the top of
21 November 2006
I've added Matt's (KC0UKK) suggestion for crystal
grounding. Matt followed the technique developed by Bob, K7HBG, but pre-wired
the ground lead. More details at the
Constructions Update page.
I've also added a caution on cleaning solder flux from the
LCD module after soldering the 20-pin connector. In a word, don't. The light
diffuser can be damaged and result in in a splotchy backlight.
20 November 2006
I received a couple of construction suggestions and
photographs from Doug, N6TQS, today and have posted them at the
Construction Updates page.
Friday, I received a trouble report about stray characters
being seen on the Z90 display. The characters appear at random and remain in
place until the Z90 is rebooted. (By the way, it isn't necessary to cycle the
power switch to reboot a Z90--you can also do it by holding down the top and
bottom soft key switches for approximately one second.)
I've had Z90's running for quite a while. The oldest has
run more or less continuously for five or six months, and I have two others that
have run close to 24/7 since mid October, without any indication of the stray
I asked the builder to return the display to me and sent a
replacement to him today. In order to verify that I was sending a known good
display, I ran one of the new displays for 24 hours without a problem. I then
ran another new display for 12 hours without a problem but when I fired up the
third new display I was able to duplicate the stray character problem. At the
moment, it looks as if perhaps one out of 10 displays show this problem, but the
statistical basis for this percentage is limited.
As you may recall, I developed the Z90 with two revision
"C" Crystalfontz displays, which became obsolete a couple of months ago,
replaced by the "C0" board, which uses a different controller chip, supposedly
100% compatible with the Epson controller in the "C" board. I've had one "C0"
revision display running almost continuously for more than a month without a
problem and a second "C0" display with at least two weeks 24/7 operation without
an error. At least two builders have completed their Z90 kits, all with C0
boards, without display problems.
I had a lengthy chat today with an engineer at
Crystalfontz, the display module supplier, and received assurances that if there
is a problem with the displays, they will stand behind them. We discussed
possible problems that could be seen with 10 or 20% of displays when tested with
the same test bed and same software, but without coming up with a better answer
than tolerance stackup on data transfer timing. The engineer suggested that I
try increasing the time the data is on the bus before firing the strobe to latch
the data into the display, although he agreed that the timing in the current Z90
software release was already generous based on the display's data sheet.
I've tried increasing and decreasing the various delay
periods in the software, using the one display that exhibits the problem. So
far, I'm unable to see a definitive correlation between delays and stray
characters. In fact, when I reduced the delay period to 200 ns, the
display seemed to work better (but not perfectly) than with 1.2us delay. The
display driver module, by the way, is posted on this site at the
GLCD page and may be seen by clicking
I am continuing to work on the problem with Crystalfontz.
If you have built your Z90, I would appreciate a brief report if you see stray
characters or not. I assume that if you are seeing stray characters, I would
have received a question, so this request is aimed more at those who have built
a Z90 and have not seen a problem.
I'll copy this note to the Construction Update page as
18 November 2006
I've had most of the day to work on my new K2-related
project and it's moving along nicely. I will provide a bit more detail and a
photo or two in a few weeks after working out a few more details.
The photo below is the Z90 Running Spares kit, which
consists of one each of all the semiconductors, spare switches and the parts
most likely to fail, such as the input attenuator resistors (should one make a
gross blunder such as transmitting into the Z90's signal input.) and the
connectors, as they are exposed to wear as they are mated/unmated. Not included
are parts related to the display or the DDS module.
Spares box with cover open
17 November 2006
The landscape crew showed up this morning and managed to
finish their work by 4 PM. The only radio related part of the job was to have
some egg-size river gravel spread around the base of my tower. Looking at it
now, it's apparent that it needs more of the same, but that will have to wait
until spring. I imagine at that time we may wish to have more house-related
landscaping work done.
I shipped two more Z90's internationally today. I believe
that there are two pending orders for immediate shipment for which I am awaiting
checks to arrive. All remaining orders are for consolidated shipping, when the
replacement panels arrive. If you are expecting to receive your kit with interim
panels and have not told me that the check is in the mail, please contact me.
And, of course, contact me if you wish to change your mind and wish to take
delivery now instead of waiting.
At this time, I know three Z90 kits have been built and
are working, and one where the builder is almost finished but has a problem.
These numbers do not count the three Z90's in my workshop for development and
general band watching.
I find that setting the Z90 for 50 KHz span, 1 KHz RBW,
skip mode "low" provides an excellent combination of bandspread and response
time. I see about 2.5 scans/second in this configuration.
The day was otherwise consumed with supervising the
landscape work, picking up the last batch of bound manuals and similar things. I
have found an hour or two for my next project and it is progressing nicely.
16 November 2006
I had set aside the day to deal with a visit from the
landscapers, but with 1.5" (nearly 40mm) of rain today, that job was washed out.
It's supposed to rescheduled for tomorrow, but walking outside is similar to
treading on a huge sponge. Perhaps by tomorrow morning the worst of the water
will have run off or soaked in and the job can be completed. Since Northern
Virginia is known for its dense clay soil, far more runs off than soaks in.
Since the landscapers did not show up, I used the time to
finish preparing a third batch of printed manuals, and dropped them off at
Kinko's for binding, to be picked up tomorrow or Saturday. My usual route back
from Kinko's was closed due to localized flooding and the creek running through
Clifton was as high as I've seen it in the 20 years I've lived here.
Fortunately, our house is on a small ridge and flooding is not a concern.
According to the Post Office's on-line tracking system, my
three international orders shipped this week are either in the hands of the
destination country customs or in the air on the way to their destinations.
Global Express Mail is pretty efficient; I mailed one package Tuesday and it at
German customs today, Thursday. The packages to Australia left Wednesday morning
from the Clifton Post Office are are in the air on the way to VK-land now,
Thursday evening, and should be in Australian customs in another 10 or 12 hours.
The price of shipping a package the size of a Z90 kit via
Global Express Mail is in the US$ 70-80 range, depending on destination country
and the exact weight. I priced competing services from UPS and FedEx and found
them significantly more expensive, on the order of US$ 125-150 for similar
delivery speed. I also understand that customs clearance fees are lower when
goods are shipped by post.
I believe that all domestic shipments for which I received
payment have been delivered. The Post Office's system for tracking packages is
slow to update, with delivery notification showing up electronically two or
three days after actual delivery, and in a few cases, the electronic delivery
notification has failed to show up at all. I've found the Priority Mail parcel
service to be very efficient, but the Post Office's tracking system is not up to
the standards set by UPS or FedEx.
At this moment, I believe that there are only three or
four customers that wanted delivery with interim panels but from whom I have not
received payment. If you intended to mail the check but have not gotten around
to it yet, please do so. I would like to reclaim a bit more of the living room
from its temporary shipping and receiving functions. Or, if you have recently
mailed a check and have not received an E-mail from me acknowledging receipt,
please let me know, as my practice is to let customers know payment has been
received the day I have it.
15 November 2006
assembled a Z90 today for a second development test bed and discovered that my
supplier shipped a quantity of 2-56 x 0.5" spacers instead of 4-40 x 0.5"
spacers. These are used only in the Z90, not the Z91. Some of these incorrect
spacers have almost certainly been bagged with the Z90 kits. If you can't see
the difference by eye, try hand threading a 4-40 screw into the spacers. It will
be immediately obvious that the 2-56 threaded spacers are too small to admit the
Please check your spacers and let me know if you received
2-56 threaded spacers instead of the correct 4-40 spacers. Future kit shipments
will be checked for the correct spacers, of course. I will also post this at the
Construction Update page.
Doug, N6TQS, has provided another suggestion for Z10000
builders and also photographs of the stand he made for his Hakko 808
de-soldering gun. Doug's information appears at the
Construction Update page.
14 November 2006
I shipped the first Z90 internationally today, as well as
two domestic orders. If you plan to take delivery with the interim panels,
please send your payment and your kit will go out a day or two after receipt.
Doug, N6TQS, reports that his Z90 is assembled and
working. That's the first "real" completion, after pre-release builds by K7HBG
and W5EWA. Doug had decided to mount the CCFL Inverter using the socket option
and found that the result is somewhat fragile. This is one of the trade-offs in
socket mounting the inverter module versus soldering it to the PCB. I've built
both ways and probably will opt for direct soldering for future builds, but
different folks may reach different conclusions. I'll add Doug's remarks to the
Construction Update page.
13 November 2006
I spent most of yesterday tinkering with my next K2
project. I'll talk about it more when it's closer to something that I know
will work and be useful, which are not the same thing. At the moment, I'm
reasonably confident that it will work, but its usefulness is another
Today has been busy getting additional kits ready to
ship, including a couple of international orders.
At the moment, I have two builders at Stage 8, one with
a bit of a problem that I'm working with him at sorting out and the second so
far without issues. I've also received more feedback based on receiving
the kit, and I'll post a couple of those comments at the
User Views page, along with a photo of the Z90 at
Stan, W5EWA's shack. I also posted a two suggestions from N6TQS on the
Construction Updates page.
11 November 2006 PM
I've added comments from Mike, W2PY, at the User's
As of 11 November, I believe Stan, W5EA and Bob, K7HBG, the two test
builders, have the only completed Z90 kits, although I know at least one builder
has finished Stage 4.
11 November 2006 AM
Stan, W5EWA, reports that re-flashing his Z90 with
firmware version 602 went without trouble. He pointed out one discrepancy in my
instructions on the Software updates page, now
fixed--the mcloader program does not use the term EEPROM; rather the box that
should not be checked is labeled Program Data.
10 November 2006
I have added a revised Z90 firmware release, version 602,
to the Software Updates page. The revision shifts one
of the stock IF frequencies from 4914 KHz to 4915 KHz for a better match with
the K2's IF frequency.
The firmware is installed into the Z90 with the
mcloader.exe program provided on your CD-ROM.
This release applies to both the Z90 and Z91.
I don't intend to make further changes to either the
Z90-Control software or the Z90 firmware until some operational experience is
collected by Z90 users, barring, of course, bug fixes as may be necessary.
I've posted a note about measuring the Z90's current during
checkout at the Construction Updates
page. Read this if you use a digital multimeter to measure current.
09 November 2006 AM
I've added the revised Z90-Control software to the
Software updates page. The revised program adds on-line
help. If you are running an earlier version, you may wish to download and
install this update.
08 November 2006
A long day in front of the milling machine. I finished
making all my remaining 0.5" x 0..5" Delrin bar stock into upper and lower
struts. I started early, around 0630 and finished around 1400 and I made 21
pairs of struts. That works out to about 10 minutes for each strut. Adding the
time to cut the stock into rough lengths and then finish to the final length
probably adds another three or four minutes to the production time, but I did
that 10 days ago. And, yes, this time I managed to keep my fingers where they
belong and away from the milling cutter.
I still have about six persons who indicated they were
prepared to purchase a Z90 or Z91, but who have not responded to my follow-up
messages. I'll send out one more round of messages to those persons, probably
later today. If I do not receive an answer within a reasonable time, I will
regard their order as canceled and will re-open the order window after meeting
any requests in the queue.
One more Z90 kit went out the door this afternoon. It
looks as if the Post Office Priority Mail is pretty consistently meeting second
day delivery, but its Delivery Confirmation service has real problems. On
Friday, 3 November, I mailed four packages, each with Delivery Confirmation, and
as of a few minutes ago when I last checked none of the packages show anything
other than Acceptance at the Clifton Post Office on the 3rd. In one case, a
customer let me know that his package arrived but I don't know the status of the
others. (That package arrived Monday.) One day earlier, on the 2nd, I mailed
three packages and received Delivery Confirmations reasonably promptly. In one
case, the confirmation must have been sent to me via E-mail within a few minutes
of delivery, and the others were a bit slower, but still showed up within a day
of the actual delivery.
Drilling holes in a strut. This is a bottom strut,
identifiable by the second, shorter notch at the right hand side, projecting
over the vise. (This notch provides clearance for the solder side of the
20-position un-shrouded header soldered into the GLCD during Stage 8.
The hole being drilled is with a No. 43 drill, to be
subsequently tapped for a 4-40 machine screw.
I set up a stop, using an angle plate and a parallel so
that I could drill one strut, remove it and place a second strut in the vise
without re-zeroing the mill table. That's a huge time saver.
06 November 2006 PM
I've added a comment from Matt, KC0UKK, at the
User Views page, with his first reactions after
opening the Z90 box.
06 November 2006 AM
I have posted a couple of suggestions in
Construction Updates, one from K7HBG and
one from N6TQS.
I've added a help file to the Z90 Control software. After
I test it with a some friendly users, I will post the updated program file and
help file at the Software updates page. The help file
is a copy of the Z90 Operating Instructions.
I picked up the box of bound documents this morning and
the one outstanding order shipped at noon. All the packages shipped Thursday
last week were delivered on Saturday, and that should mean Friday's
packages will be delivered today.
05 November 2006 PM
I dropped off a box of 10 sets of documentation to be coil
bound this morning and will pick them up tomorrow. I have one outstanding order
that will ship Monday after I pick up the bound documentation.
A series of posts in the Elecraft forum has discussed
whether the K2's RF output has overshoot on some bands in SSB mode. In other
words, does the initial few milliseconds of audio input cause the output power
to exceed the target. I've run a short test at 7 MHz with varying degrees of
audio drive. The results may be viewed at the Documents
page or by clicking
This is Sweepstakes CW weekend. Here's a look at the 20
meter band, 14000-14100 from Clifton VA.
04 November 2006 PM
After this morning's measurements, I ran a few errands and
returned to start producing the next batch of documentation. I now have 10 sets
printed, ready for me to insert the tabs and run them over to Kinko's tomorrow.
I should be able to pick them up Monday. I also went through the Stage 1 parts
bags, removed the two picofuses and replaced them with the 1.1A polyfuse.
At least two of the kits shipped Thursday and Friday have
arrived. One to California and one to Michigan. That's excellent service from
the Post Office for those two packages. I'm not sure about the other four, as
the Post Office's tracking system seems to have variable update speed; sometimes
the delivery will be reported within minutes and other times the report does not
arrive until the late night batch update.
04 November 2006 AM
I have posted my conclusions and a link to the supporting
measurements concerning top versus bottom crystal grounding in the Z90. My
bottom line conclusion: No real performance difference between top bus and
bottom individual grounding. More information at
Construction Updates and the supporting
data may be found by clicking
here or visiting
the Documents page.
03 November 2006
Three more kits went out the door today.
I have now sent E-mail messages to all Z90 customers
asking about their desire to take immediate delivery or wait for the re-made
panels. About one-third of my E-mails have not been answered so follow up
messages will be required. If you have not responded to my messages, please do
so as soon as you can.
I've been working on a more efficient method of
handling the paperwork and the mechanical aspects of packaging the kits and
getting them out the door with a minimum of errors.
All individual stage parts bags have long been finished
(except that I have to open Stage 1 and replace the picofuse with a polyfuse)
and are individual boxes. When I'm ready to ship an order, I print a detailed
packing list / check list (with about 50 items) and check off the box when each
bag or part goes into the box. I pre-prepared 10 Z90 cabinet assemblies, punched
the chassis pan, selected front and rear panels, made up the upper and lower
struts and the like. It seems that small to medium size batches work the
best for me.
Tomorrow's batch job will be to print and organize for
binding six or eight document sets. I print these on an HP 4000 laser printer to
provide the best B&W graphic quality I can and also to keep the documentation
reasonably up-to-date. I then take the printed document package, insert tabs and
deliver them to the local Kinko's for coil binding.
As I've mentioned before, documentation is a moving target
and it's important that builders check the Construction Updates page before plugging in the soldering iron. Bob, K7HBG,
has provided two good suggestions, including a new alternate crystal grounding
02 November 2006
I shipped three kits today, and will ship another three
between tomorrow and Monday. Also, the last of my delayed cabinet order arrived
from TenTec. I have (fingers crossed) no outstanding parts order, save for the
replacement panels from emachineshop.
I expect to receive comments and suggestions and
recommendations from builders that will be of interest to all those building the
Z90 or Z91 kits, including the Z10000 buffer amplifiers. And, the written
documentation that I mailed today with the kits is already out of date because
of comments I received this afternoon from Bob, K7HBG. Accordingly, I've created
a new page Construction Updates to
present this information. Before you start building your Z90 or Z91, you should
check Construction Updates. I've also added a PDF of the most recent errata
sheets that may be accessed by clicking
here or via the Documents page.
I've also had a question about the difference between a
picofuse and a polyfuse; why Stan experienced problems with the picofuse and why
I went back to the Z90's original polyfuse design. Here's an edited version of
To summarize the fuse types:
- Picofuse -- a traditional one-time only fuse,
made in a very small form factor resembling an 1/8 watt through-hole
resistor. When it blows, you have to replace it. It is soldered in, so
replacing the fuse requires removing the old one and soldering in a new one.
- Polyfuse -- automatic resetting, when the
overload is removed. This is a permanent device and should not require
replacement during the life of the Z90. You may think of a polyfuse as a
miniature solid state circuit breaker with automatic reset.
When the polyfuse is installed, there are no problems with switching on the
Z90 using a high current power supply, as polyfuses are not nearly as
sensitive to very short duration current spikes as are the picofuses. And,
that short, high value current spike at turn-on was popping the picofuses. The
current spike lasts only a few milliseconds, but that turns out to be enough
to blow a picofuse. My error for not testing the picofuse with anything other
than either a wall wart or an HP laboratory supply that I use for development
I shipped Stan's kit with a picofuse, as I had decided it was a better choice
than the polyfuse I used during development. That turned out to be an error on
my part, as my original polyfuse choice works better with the Z90,
particularly when powered from a supply capable of delivering many amperes.
All kits are shipped with a polyfuse, and builders will not experience any of
the problems Stan did with blowing the picofuses. (The Stage 1 parts bag says
it contains two picofuses, as it was printed before I made the change. The
errata sheet contains an appropriate correction.)
Speaking of documentation, here is the package that
accompanies the Z90 and Z91.
The documents are consolidated into a single book, coil
bound so that it will lay flat on your desk top. This is about 225 pages long
and covers the Z90/91, the Z10000 buffer amplifier and the Z10010 4915 KHz
The CD-ROM has PDF copies of the documentation as well as
the Z90-Control program and the current (as of shipping) firmware and a loader
program for re-flashing the 18F4620 with new firmware.
01 November 2006 PM
Today seems like non-stop activity. Among other things, I finished printing
half a dozen complete manuals and dropped them off at the Kinko's copy center
near George Mason University to be coil bound. That Kinkos is staffed largely
by part time GMU students and the Z90 documentation impressed the lady at the
counter who said she had studied engineering.
The documentation package is about 225 pages long and contains the following:
- Z90 Operating Instructions (approx 55 pages)
- Z90 Assembly Instructions (approx 92 pages)
- Assembly Support Documents (approx 23 pages total)
3.1 11x17 fold out schematics
3.2 11x17 fold out schematics with voltage and waveforms for
3.3 Parts location map with index
3.4 Parts list
- Z10000 Buffer Amplifier Assembly and Operating Manual (approx 45 pages)
- Z10010 4915 KHz bandpass filter Operating Manual (approx 8 pages)
Later tonight, I will finish packing up several kits to
ship this week, except for the printed documentation. They should be ready to
go out tomorrow morning after I pick up the bound copies.
Stan has an update that I've posted to the
W5EWA build page. He is now finished with the
build and has installed the enclosure and panels. Stan's total build time was
12H 25M. The Z90 should be a good three or four day kit, although I built one
prototype board in a single marathon session.
I mentioned a few days ago that I would post a couple of
photographs showing the Z90's struts being machined. Catching the end of my
finger in the end mill threw a damper on further photos, but here are two that
I took before my error. (No real damage, but it reinforced the lesson I should
have known before to keep my hands away from moving cutters. I'm lucky it was
only a nick that a band aid fixed as it easily could have been a serious
injury. A 1" diameter sharp milling cutter driven by a 1HP motor is nothing to
fool around with.)
Squaring the ends of the Delrin stock for upper and lower
Z90 struts. 12 pieces of 1/2" x 1/2" stock are being squared at once. The
milling machine has a 1" diameter end mill.
The other end of the Delrin stock is placed in contact with
an angle plate.
01 November 2006 AM
As usual for the first of the month, I've moved the October
2006 page to the archives. It may be accessed from the link at the top of this
page, or by clicking here.
Stan, W5EWA, has finished his advance-build Z90 through Stage 8. This
includes all electronic work, including plugging in the LCD display and
softkey switch board. All that remains is the enclosure work, so Stan's
about an hour away from completely finishing his Z90. I've posted his most
recent build notes and photos at the W5EWA build
Based on his success, I'm ready to ship the orders for which I have received
payment. I have a few small changes to make in the documentation based on
comments from Stan and Bob, K7HBG, the two advance assemblers. That should
be done this morning and then I will print the documentation and run it over to
the local Office Depot be bound. The documents will be coil bound, similar to
the Elecraft's manuals, so as to lay flat during assembly. I plan to bind all
the documents into a single entity, to make it easier to keep together. The
11"x17" oversize schematic and troubleshooting pages will be folded to 8.5" x
11" size. I probably will include the Z10000 and Z10010 documentation in the
bound set as well so as to have a complete package in one location. Inevitably,
of course, there will be a separate errata sheet as I've found some errors in
things previously printed, such as some bag labels.
I also found myself writing a caution note or two that should be unnecessary.
Part of the final assembly requires you to bend a strip of thin tinplate shield
material into an open-top box. The tinplate is thin (0.008" or 0.2mm) and has
sharp edges. So, consider this yet another reminder that sharp edges can cut
your fingers. You should knock off any burrs or sharp edges with a small file or
sand paper before bending the shield. You may also wish to cut the corners at a
45 degree angle and round them off for the same reason. I resisted the
temptation to remind you that soldering irons are hot, that you should not eat
solder as it contains lead and that you should not run whilst holding scissors.
I doubt that the packages will go out today, as I have some other errands
that will consume significant parts of the day.
I also successfully completed PayPal's registration process to receive
payment. I've signed up for PayPal as a way of helping international customers
avoid the large fee they otherwise would pay for a direct bank-to-bank transfer.
(My bank also charges me to receive the funds transfer, so there's a bite on
both ends of the transaction.) However, PayPal takes a not-inconsiderable
transaction fee for their service, so I do not plan to accept PayPal payment for
domestic US customers.