开云体育

Guys:

I own an HP 6381A with the on-board back up battery on the memory board.

Since these batteries are becoming increasingly difficult to find with the leads welded to the battery body,?
I recommend you purchase a socket and replace the battery with the socket.? Don't rely on Batteries-Plus,
as they don't do this procedure any more, and don't try to solder leads to the battery directly as the heat
from your soldering iron may cause it to explode!

I found the sockets?on Amazon at:



(Make sure you select the "CR2477" box!)?

Afterwards, changing out the battery on the memory board is a much more simplified procedure.?
Make sure you order the battery socket that lies flat on the board with the two pins out the bottom of the socket
and not the vertical-mount socket that mounts perpendicular to the board.? Also, pay attention to
polarity when you mount it!

I don't recall which board is the memory board, but it's the only board with a back-up battery?
mounted on it.? It's an easy find when you look down into the boards with a penlight.

Rick Hendricks
KE0GB

Hi Shane,

?

I am working on reviving a HP 8921A, that has the memory battery of 3V that is PCB mounted LIPO type. These batteries will supply quite a bit of current. The AAA Battery may be too much drain for it. The technology is 74HC era .

Hope this is of some assistance .

73s

Bill M.??? (VK6II)

Hello all,

Just obtained an HP 8935 test set that has been sitting unused for several years. Upon power up the display indicated "AA memory battery low. See HELP menu"
I removed the rear cover and found the AA battery holder, corroded and nearly dead batteries. Not unexpected. Cleaned it up, put in new AA batteries, powered up the set and started checking various functions. So far so good. Powered the set down.

Returned a few days later and powered the set on. After self check the display now reads " Internal memory battery low, See Help menu"?
The HELP menu just says the internal memory battery is not user serviceable- contact HP customer support. ( sheeyah right ! )

Ok, before I start disassembly of the set, does anyone know which board the internal memory backup battery is on? What type it is? Solder in or in a holder?
?Any help is appreciated.

Thank you.
Shane Ke6jz

What is the Hi-Stab option module in the 8924C?? Does it power only the oven in stby or the osc. too?
I was hoping to provide the capability in my 8920a with a 08920-61035.?
I haven't found a CLIP for the 8924c.? The one in FILES is really the 8920a.

I tried a second A16 board. This one gives the same "Calibration checksum incorrect. Writing to default values" message, but continues to boot. At the completion of booting, it says something about errors in some of the CDMA tests. I don't care about the CDMA tests. The manual states that if certain modules are replaced, calibration data for them must be entered by PCMCIA card. I think this assumes that the replacement module came straight from Agilent. It doesn't list the A16 as something that requires recalibration. I tried to find a calibration procedure, but, so far, I haven't been able to find one. There are a number of diagnostic tests that can be performed, and I intend to perform those that pertain to analog testing. There are also a series of verification tests that can be performed. If all that seems OK, then I think I am good to go. Meanwhile, I was going to see if I could get the "E" model up and running. About a minute after powering it up, it seems to have blown a power supply capacitor, emitting a loud pop, followed by power going off. So, I'll have to tackle that next.

Not to Hijack, but what is the module in the 8924C?? Does it power the oven only or the osc. too?

Actually, I have also kept an old IFR with analog meters and TCXO calibrated at room temp after
5 minutes.? Never any rolling numbers, and close enough for ham use.

On Wed, Aug 10, 2022 at 06:28 AM, alfonso wrote:

thanks for the info but unfortunately my power supply put on another 8920 works correctly (at least when I tested it a while ago) now I also have other problems and, perhaps because of me. I am angry with myself.

10/08/2022 02:34, zl1cvd wrote:

I have seen 2 causes for this type of fault.

1. Faulty power supply - check all power rails are the correct voltages. These units all suffer from dry / cracked caps in power supply. The cure is to replace all electrolytic caps in the power supply with equivalent value 105C types. For any fault in 8920, 8921, 8922, 8924, E8285A, 8935(E6380/E6381)? you should first check power supply and output of any regulator board - sometimes separate to power supply.
2. Faulty A19 Measurement unit - refer to 8920 CLIP for full circuit of the measurement unit.

ERROR 223 error is not caused by the power supply PSU, it should be caused by the failure of the A19 board. You can try to replace A19 to troubleshoot, and the failure of A19 is likely to cause the A7 board to fail as well.
?
--

Regards,

?
Box

thanks for the info but unfortunately my power supply put on another 8920 works correctly (at least when I tested it a while ago) now I also have other problems and, perhaps because of me. I am angry with myself.

On Tue, Aug 9, 2022 at 06:00 PM, @DonBox wrote:

On Tue, Aug 9, 2022 at 05:34 PM, zl1cvd wrote:

I have seen 2 causes for this type of fault.

1. Faulty power supply - check all power rails are the correct voltages. These units all suffer from dry / cracked caps in power supply. The cure is to replace all electrolytic caps in the power supply with equivalent value 105C types. For any fault in 8920, 8921, 8922, 8924, E8285A, 8935(E6380/E6381)? you should first check power supply and output of any regulator board - sometimes separate to power supply.
2. Faulty A19 Measurement unit - refer to 8920 CLIP for full circuit of the measurement unit.

Thank you for your reply and suggestions.

Power supply on the electrolytic capacitors I have replaced all, A19 on the J1 detection point +5v and -5v are normal, currently suspected of A19 data loss, or other problems.?
--

Regards,

?
Box

8920A/B and 8921A Test Set Assembly Level Repair (.pdf 13.86 MB)
669 pages

?
--

Regards,

?
Box

On Tue, Aug 9, 2022 at 05:34 PM, zl1cvd wrote:

I have seen 2 causes for this type of fault.

1. Faulty power supply - check all power rails are the correct voltages. These units all suffer from dry / cracked caps in power supply. The cure is to replace all electrolytic caps in the power supply with equivalent value 105C types. For any fault in 8920, 8921, 8922, 8924, E8285A, 8935(E6380/E6381)? you should first check power supply and output of any regulator board - sometimes separate to power supply.
2. Faulty A19 Measurement unit - refer to 8920 CLIP for full circuit of the measurement unit.

Power supply on the electrolytic capacitors I have replaced all, A19 on the J1 detection point +5v and -5v are normal, currently suspected of A19 data loss, or other problems.?
--

Regards,

?
Box

I have seen 2 causes for this type of fault.

1. Faulty power supply - check all power rails are the correct voltages. These units all suffer from dry / cracked caps in power supply. The cure is to replace all electrolytic caps in the power supply with equivalent value 105C types. For any fault in 8920, 8921, 8922, 8924, E8285A, 8935(E6380/E6381)? you should first check power supply and output of any regulator board - sometimes separate to power supply.
2. Faulty A19 Measurement unit - refer to 8920 CLIP for full circuit of the measurement unit.

ok thank you i hope you can solve it as soon as possible i can't do anything about it now, as soon as i have the .bin file i'll upload it to the new eepromm and test it unfortunately i have to do it myself. i don't have much spare parts available, in the meantime (time permitting) i'm studying the A19 diagram

regards.

On Mon, Aug 8, 2022 at 02:14 PM, alfonso wrote:

hello, no I have not corrected the error, but I have kept the instrument switched off for a long time and now it only does the boot. and, all the lights remain on the A7 board, you only hear the boot beep and then black screen at the moment I cannot do anything at all for the reason that I have not installed the GBIP and therefore do not have the RS232 available.

?This phenomenon, which I have also encountered, seems to be that certain motherboards are not plugged in properly.
--

Regards,

?
Box

--

Regards,

?
Box

Now I can't operate anything except I can move the cursor when I turn on the computer. So after I fix ERROR 223 (A19 board), if I can operate normally, I can try to download the BIN file of A7 board 28C.
--

Regards,

?
Box

ok it doesn't matter to me, I've bought a new 28c and would like to try programming it with a definitely working .bin file to see what happens if it's not a problem for you it would be appreciated then for the A19 I was investigating but now I have to try to get it out of the coma and then you will see the file attached to my email would be the best once I've tried it I'll say how it went.?