| General > General Technical Chat |
| Need opinion RE HP/Agilent 6623A power supply |
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| casinada:
It has been a while since I repaired them. If I remember correctly If one of the output boards fail the self test the power supply will fail to operate. You can bypass the self test by changing a jumper on the GPIB board. The rest of the outputs will work. I think you can also unplug the control connector from the GPIB board to the defective output board and the power supply will also start. Good luck. Service manuals are available and probably describe the troubleshooting procedure better than me. :) |
| free_electron:
you can reset the model number through a GPIB command. if no model number is provided the firmware doesnt know the range of the installed modules. looks like the eeprom (93c46) is fried. the GPIB controllers are NOT interchangeable ! ( the smd version is NOT the same as the thru hole version ! ) especially on the display part. |
| ScribblesOnNapkins:
casinada: Thanks for posting those pictures. I have an HP 6627A and I noticed something. Your photos show U338 as a group of discrete components. In mine and all the copies of the manual it's a single large hybrid. 1. Can you please post more photos of just that sub assembly. 2. Does anyone have a copy of the manual where that section is described? In the copy I have from the following URL it's just described as a sub assembly. http://literature.cdn.keysight.com/litweb/pdf/5989-6871EN.pdf?id=1268102 PS: Don't you love how they hinged the top cover and used a minimal number of screws to hold each board in. |
| SV1EOR:
I have a Hp6627a on my bench in order to service one of the output boards with problem in U338 Hybrid as the trouble scouting charge tells me. Has anyone found the circuit or a part list for it in Hp manuals? I have the parts on the small hybrid boards, but I'm not sure ... |
| rfclown:
I have a few 6627,6624. The pros: 1. Amazing for the eBay price. 4 channal clean linear HP GPIB supply for $300 bucks? (just looked on eBay and this was on top, including shipping) 2. Solid. I've used them for about 30 years (not the same one) with no failures/issues Cons: 1. Loud 2. Display only shows one channel at a time (if I could change only one thing, it would be this) 3. connections come out the back. You can make something to help accomodate that (see picture). 4. heavy I used these at Motorola. At one time I had a setup where I needed many supplies, and I used three of these (12 channels). Used LabVIEW/GPIB to sequence proper power up and down and ensure no desctructive fault conditions (might shut down one supply if another one current limited). When I left Moto after 22 years and started contracting, I bought equipment that I was familiar with, which included these DC supplies. I never had any issue with them. I couldn't believe how cheap I could get these things on eBay. I later got some single channel 35V and 60V units (really heavy). I still have one in my bench stack, but today I find that it not the first DC supply that I turn on at my bench. Why? 1. Loud Most of the time I'm doing something which my small no fan 18V/2A linear supply can handle. No fan, so I can hear the transformer hum. With the 6627A when I turn it on it sounds like a jet starting up. |
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