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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And a final picture of the twin transformers in the working power supply. 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 70004a out.
Hewlett Packard HP a Display With b Optical Spectrum Analyzer | eBay
I was lucky to have bought a FLUKE D differential voltage probe this year at Friedrichshafen to the nice guy with grey hair and glasses that 7004a mostly Ho stuff. Something was drawing more current than expected and the current-limit protection was tripping. I was happy to find it actually worked I used a thin teflon tube and a copper wire to recreate the four turns that form the secondary and guess what, it worked!!
I built this “adapter” thing as a temporary solution, you too know what that means: I bought this cheap A color display as faulty.
This last one required some improvisation because it is a quad-transistor instead of dual, and the DIP package is very different.
HP a Spectrum Analyzer Display Mainframe W/ HP b Pattern Generator | eBay
This is the beast on the bench, that PCB looks very timidating to me. Could this be fixed? There is a current sense resistor and this is what current looked at turn-on try:. This paid for itself in just this repair. 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.
Can 7004a tell one from the other? Do you see that suspicious potting that squeezed outside the can in one of them?:. 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. 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.
Showing Results for Keysight Technologies (Agilent HP) 70004A
I confessed before that I killed a few components on the process, and I could not find replacements for some of 70004q You can see the power supply slowly increasing the current at turn on until it gets too 70004 before it starts regulating the voltage, and quits.
You’ll probably want to use an isolation transformer and differential probes, and keep one hand on your pocket at all times. The block diagram was invaluable, this switching power supplies are complex. Home Projects Music Photo. One day, it refused to turn on.
I did not know where to start. You really need to know what you are doing before probing and testing a thing like this live. After many hours of testing and probing, and and few components that exploded in the process most times my fault I found there was a transformer with a 14 ohm leak between primary and secondary. Yp surpise, the secondary jacket was burned and touching the primary in one spot:. I could see the power LED flash briefly upon turn-on and then This board is a latter revision than the ones that appear on the schematics but there are not many changes.