If you are reading the frequency of an FM transmitter, this is normal - its frequency changes with modulation.

If you are reading a non-modulated signal, and it's substantially higher than the noise, the analyzer has a problem.

There is no smoothing or averaging function for frequency, only for amplitude.

When reading a transmitter's frequency, the last few digits jump around so much it is hard to determine what is real.? Is there a setting to normalize or smooth that so I can warp it onto frequency?

Pat

Now I can confirm that the problem is on the A7DCU motherboard. I used 8922 motherboard installed on it and was able to boot up.

Hi.
unfortunately I haven't tried to solve the problem yet due to lack of time.
I hope for some response to your appeal :-)
Maurizio

Hi Maurizio
How did you solve this problem.

It happens to me too, same problem.
I've never investigated.
Maurizio?

I must have repaired 8 or 9 of these now. I always double & triple check all power supply rails. I've seen all sorts of errors fixed by replacing all electrolytic caps in PSU & regulator board.

Also tried turning an E into a C by replacing with 4 different A16 boards I purchased on eBay - no joy. I also have a complete set of C model boards that I stripped from a transit damaged case. I could not get any combination to work so gave up. This made me think it was a motherboard link / jumper but I compared & could not figure out how the E / C model is determined. A16 boards are the same and even trying to load C firmware from PCMCIA didn't work.

I was going to contact Rick @? www.amtronix.com/? but moved QTH so the 8924 is still packed away in the container. I have purchased firmware from him in the past & from all accounts he is the go to person for solving anything to do with these series of test sets.

73 om de Chris ZL1CVD

An update. I received the used A16 card and installed it. Now, I get a "Calibration hash sum incorrect. Writing to default values" message. Booting proceeds no further. The manual says than when replacing the A16 card, the cal constants ROM from the old card must be transferred to the new one. I did that and the same thing happens. The manual also says that once the message appears, it should complete booting, and work, except it won't be calibrated. Mine is stuck at that message. I have no clue where to go next, and the manual isn't any help in that regard. Almost all of the trouble shooting information in the manual assumes that the unit boots. I think my only option at this point is to see if I can get the "E" model to operate. It was operating when placed in storage, but that was some time ago.

Thanks Yuri for the reply. Unfortunately, I don't have the proper equipment to do that. It seems that the prom chip wasn't bad after all. When I transferred those chips to the A16 card from my "E" model, it now boots. But, it thinks it is the "E" model. It was something else on the A16 card. I was under the impression that it was the prom chips that determined the model number. Not so, it is something else entirely. I do have a used "C"model A16 card on order, and hopefully, it will solve the issue. I really hope I can get this instrument going again. Though I don't use it all that often these days, I have no way of replacing its functionality.

开云体育

Few additional notes about "leaked" EPROMs data recovery.

CMOS chips 27Cxxx allow quite deep lowering of Vcc, some to almost 3.3V level, and sometimes incompletely erased chips that tested blank by regular programmer can reveal (almost) complete data at very low Vcc. NMOS chips (27xxx) is turning to "all zeros" at much higher Vcc levels.

Same trick worked for me when I tried to recover "leaked" 2816 calibration EEPROM from Marconi 2955 service monitor that I had in the past (it was Xicor part if memory serves me correctly).


73 de UA3ATQ/KI7XJ (there was typo in callsign in previous message) ;)

--
Best regards,
Yuri ? ? ? ? ? ? ? ? ? ? ? ? ?mailto:yuri@...

开云体育

Hello,

Friday, July 29, 2022, 0:23:21, wspx472 wrote:

After sitting a couple of months, my 8924C now displays a "ROM Checksum Error". I also have an "E" model I bought mostly as an organ donor for the "C" model. I put the A16 card from the "E" model in the "C" model and now it boots, but thinks it is an "E" model. It is also showing hardware failures. ._,_._,_

Is there regular 27(C)xxx EPROMs? Sometimes I was able to extract original data from "leaked" EPROM chips by multiple reading at lower than standard supply voltage (I have EPROM programmer with customisable voltages and pulse widths in addition to standard profiles for EPROMS from different manufacturers). "Programmed" bit (charged gate capacitor) reads as 0, while discharged gate capacitors reads as "1". With time, capacitors discharge and some may go below threshold at regular Vcc. So, gradually decrease supply voltage and do multiple readings, to see as many "unstable/floating" zeros as you can (for manual work chip compare function may do, if locations and data of mismatches is clearly shown). At some voltage whole chip will start to read as zeros, so be careful if you will try to automate this process.

After you recombine all "lost" zeros to image files, program blank chips with this files and try if checksum is ok. Do not erase originals, sometime you need to dig for more "lost" zero bits.

73 de UA3ATQ/KI7XI

--
Best regards,
Yuri ? ? ? ? ? ? ? ? ? ? ? ? ?mailto:yuri@...

After sitting a couple of months, my 8924C now displays a "ROM Checksum Error". I also have an "E" model I bought mostly as an organ donor for the "C" model. I put the A16 card from the "E" model in the "C" model and now it boots, but thinks it is an "E" model. It is also showing hardware failures.

I transferred the 2 socketed memory ICs from the "C" model card into the "E" model card in hopes of making it once again realize it is a "C" model. It seems which model it is, is stored some place else, because it still thinks it is an "E" model. I have ordered a used A16 card off eBay in hopes of fixing it.

The A17 card from the "E" model has a bad battery. A replacement has been ordered. If I can't get the "C" model going, I hope to at least get the "E" model usable.

Has anyone else has a similar experience? Where on the A16 card is the model stored? The cards look identical.

I have an 8924C with the same problem. Looking like it is the boot ROM. HP part number 08920-87168. They seem to be unobtanium. Anyone know where I might find one?
I did try an A16 board from an "E" model, and it does boot, sort of. It now says it is an "E" model, and gives self test failures.

the error 200 means that one of the boards is not communicating or holding the serial bus down.

you may want to run the diagnostics and see what it says.? The?MSDIAGS3 will run the self test and you can see the errors there or look at the messages

kind of a PITA to troubleshoot unless you have another unit to test boards in.

The 8924 has a ton of boards in there for the cellular stuff?

If it no longer has the power-on settings saved, this suggests that the memory battery needs replacing.? Then with a new battery, to make it again act like an 8920 on power-up you can follow the instructions here:

As to the other error message, I am not an expert on this unit, but the assembly level service manual indicates that it is a serial bus communication error associated with "any non-optional assembly" and that : "This checks the ability of the Controller to communicate with any hardware on the bus."? Not that specific, unfortunately.

I would suggest re-seating various connectors, etc., that may have been disturbed during the power supply repair.? It has been years since I took mine apart to work on the power supply so I can't remember any specifics of the disassembly.

It also wouldn't hurt to try re-seating all of the modules, even if you didn't remove them for the power supply repair.? Sometimes, this fixes strange problems.

The manual can be downloaded from:



There may be further relevant information in the manual.? It's about 600 pages and I just checked for the error message in question.

Hope this is of some help.?

KE6CD

So I recapped my HP8924C power supply because I had the intermittent wouldn't power on issue. But since then I lost my power on default settings and was presented with the cell site call screen instead. My self tests now fail with error 0200 and the input power shows between 3.25 - 3.5 watts with nothing connected. Self tests point to a problem with the input module but it was working just fine before I recapped the power supply.?

I tried another power supply that I also recapped but I am getting the same results

I am suspecting one of the voltages coming out of the power supply may be slightly off, but also the power supply won't run with no load connected.?

Anyone have any pointers on what to look for?



Thank you!

Alberto,?

I hope you found the files that you needed. If not, just subscribe to the group. I believe A.18.10 FW requires a newer memory board than what I have. Let us know if you are successful.?

Greg