HP 8643a internal battery?

[rz]

I've got an HP 8643a signal generator with error code: 14,020,122 and 2 messages in the queue which was "Hardware failure 14", "Calibration error 2". The function of the generator was all checked and worked fine except calibrating every start up.

After check the assembly manual, the error code means power supply problem and internal battery dead for calibration data. I want to replace the battery first.

Who has the model of the battery? or photo of the battery or the DCU unit?   

Thank you. 

[coromonadalix]

ArtekManuals have the service manual for 25$ usd ??

Googled a lot, i did not see any battery reference,   i would guess an 3 - 3.3 v battery ??

Unless you dismantle the cpu board with anti static protection to take some pictures ...

[tkamiya]

Battery is 3.6V NICAD.  Size is about the same as AA battery except it's a bit shorter and has lead on both side.  If you open the top panel, there is a section with aluminum shield with 3 RF connectors.  Unscrew one screw and it will open.  One of the card has that battery.

Instead of Nicad, I used NiMH battery.  Yes, charging parameters are different but it's so low current, I never had any issues. 

I'm not opening mine to take pictures, but once you look, it's quite obvious.

Remember to lift from your knees, not the waist.

[rz]

Thank you. I find a picture according your description. Is that this model ? I think it's rarely seen today. 

[tkamiya]

Yes, that is it.  ANY 3.6V, 45mAH or higher will do.  I believe that one is a NiCad.  As I said earlier, I used NiMH 80mAH or something and it's been working wonderfully.

In US, these kind of batteries are abundant. 

[coromonadalix]

https://www.osibatteries.com/p-18471-sanyo-n-sb3-battery-36v-nicd-2-pin-axial-leads.aspx

Or you can find an battery with wires and solder them to the board ??

https://www.ebay.co.uk/itm/For-Siemens-S7-300-6ES7971-1AA00-0AA0-3-6V-PLC-Replacement-battery/143057428880?hash=item214ee32190:m:mC_lLTR-zcpbNWI2UNjj2iQ&var=442021814469

[tkamiya]

I suppose so.  The point I was trying to make was, it isn't all that critical.  Whatever is at the right voltage and enough WH, and fits will work.  OP isn't from US so it might be difficult to obtain the same stuff we can.

On mine, the battery I chose was little too fat.  I worked around it by placing it on back of the board.  (it has little more space on back than front)

[rz]

found a battery may suitable for it.   14.1×16.5mm, NiCd 3.6v 150mAh.

The 8643a starts without calibrating and error code for about 3 days, then it start with calibrating and error code again. It confused me. 

[coromonadalix]

Maybe some bad contacts, socketed parts not properly seated,  bad solder joints etc ...

The error is still the same ?

Maybe some sram, ram, rom, eeprom corruption,  it doesn't store it properly ??   remove the cpu board and check it closely, you have lots of axial electrolytics capacitors  ... 

[tkamiya]

You didn't solder a wire directly to the battery, correct?  Did you use one with solder tab?

Use of socket can create problem as current through is so low.  It doesn't break the oxidation layer, so it may be "insulated" by it.  Soldering directly can destroy battery, especially rechargeable ones.  Also, you'll have to have power on or off but keep plugged in for at least over night to store enough charge.

It could also be a defective battery.  I had that before myself.

Lastly, you could check the charging current and draining current to make sure it is in reasonable value.

It will work.  It's a great signal generator.  I have three 8644.  I've done batteries on all 4.  (one was sold)  One showed weird symptom.  It will recal every time but it did remember the last setting.  There was a damage to a board on THE OTHER SIDE of the PC board....

[rz]

It has started normally for more than one week. So, I think it maybe the internal battery has been depleted due to long-term storage without power supply. Now, the battery is charged, the instrument back to normal.

[tkamiya]

You are good to go then.  Congratulations!