Find great deals for HP a Spectrum Analyzer Display Mainframe W/ HP b Pattern Generator. Shop with confidence on eBay!. Find great deals for Hewlett Packard HP a Display With b Optical Spectrum Analyzer. Shop with confidence on eBay!. Software and documentation supplied. This service guide is part of an Option OB3 package which includes: HP A Service Guide. HP A Component.
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HP a Spectrum Analyzer Display Mainframe W/ HP b Pattern Generator | eBay
This last one required some improvisation because it is a quad-transistor instead of dual, and the DIP package is very different. There is no way to check one of the blocks of the power supply alone, you have to give it power and hope for the best. Home Projects Music Photo. I used a thin teflon tube and a copper wire to recreate the four turns that form the secondary and guess what, it worked!!
HP A SERVICE MANUAL Pdf Download.
One day, it refused to turn on. Many suggested changing every capacitor in the board, something I was not going to do, I wanted to find what the fault really was all capacitors turned to be ok:. High voltage, big and the troubleshooting will need to be done live.
I bought this cheap A jp display as faulty. There is a current sense resistor and this is what current looked at turn-on try:. The supply operates a high switching frequency and many parts of the circuit are shorted at DC, so I could not find this until I took both transformers out.
Showing Results for Keysight Technologies (Agilent HP) 70004A
Knowing I had nothing to loose, I went and opened the transformer can with a Dremel, and removed the resin with hot air and tweezers, carefully to not damage the windings.
This is the beast on the bench, that PCB looks very timidating to me. You really need to know what you are doing before probing and testing a thing like this live.
I could see the power LED flash briefly upon turn-on and then You’ll probably want to use an isolation transformer and differential probes, and keep one hand on your pocket at all times.
After many hours of testing and probing, and and few components that exploded 700004a the process most times my fault I found there was a transformer with a 14 ohm leak between primary and secondary. I did not know where to start.
The block diagram was invaluable, this 70004a power supplies are complex. No surpise, the secondary jacket was burned and touching the primary in one spot:.
This board is a latter revision than the ones 07004a appear on the schematics but there are not many changes. I was happy to find it actually worked Could this be fixed?
I was lucky to have bought a FLUKE D differential voltage probe this year at Friedrichshafen to the 7004a guy with grey hair and glasses that sells mostly Fluke stuff. I built this “adapter” thing as a temporary solution, you too know what that means: I confessed before that I killed a few components on the process, and I could not find replacements for some of them: Do you see that suspicious potting that squeezed outside the can in one of them?:.
Something was drawing more current than expected and the current-limit protection was tripping. This paid for itself in just this repair.
70004A Color System Display
Can you tell one from the other? You can see the power supply slowly increasing the current at turn on until it gets too high before it starts regulating the 70004s, and quits. And a final picture of the twin transformers in the working power supply.