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Hi Harvey Regarding There's a philosophical point where you say: 1) these might be bad, I'll replace then all. 2) I'll only replace the ones that I know are bad. I agree with line 1 in this case but

Here you go. All are 105C. ================================ C32, C43 0180-3068? 470u/12v Sprague? 672D477H012DM5J Sangamo? 301AEM471U012B3 ESR 0.12 Ohm max Max. ripple current 1.3A

Gene, The cabling looks correct between the modules according to the document I have in front of me. If all the other modules are showing up in the map the 70900A should be there to. The issue seems

sounds like case #1 to me <grin> I've seen people who say "replace them all" I've seen people who say "replace only bad" As a philosophy, neither is likely right. Harvey

After finding no replacement VFDs under $230 plus tax on eBay, I located a company called PDA Parts that has the Samsung INB-12MM53T VFD in stock. It's the latest iteration of the 53132A display and

In the ones I've repaired, every one of those capacitors in that central column have been bad, with no exceptions. Just FYI. Heh, one of them was particularly weird. The lead *twirled* within the

There's a philosophical point where you say: 1) these might be bad, I'll replace then all. 2) I'll only replace the ones that I know are bad. To me, it depends on how difficult it would be to replace,

Damn. :-( I have no direct experience with them, but a lot of people have said they are actually pretty good. -Dave -- Dave McGuire, AK4HZ New Kensington, PA

Turns out that it's the VFD in my 58503A that is bad, and not the driver chip. The good news is that I don't have to do any PCB rework. The bad news is that I have to find a replacement VFD at a

Hi Gene, I believe you may have wrong “HP-MSIB/HP-IB Address” setting on your 70900 unit. The plug-in unit on the address map is based on their hardware MSIB/HP-IB Address setting not by default!

Steve, Thanks for your input. I believe the switches you refer to for the 70900A set the Address Map and Slave/Master. Could incorrect settings on the 709002A and 709005A stop the 70900A from being

Craig. First off big thanks for your input… Agreed that verifying system configuration needs looking into. The read cabling looks Ok I believe. Confidence test has passed…OK? What I see on the

Hi Tom Thank you for looking up the part numbers please look at the xl document I have put onto the HP 70900 folder in the HP 70000 on this site as I am using it to compare the values of the

From the 70900B CLIP: C32 0180-3068? 470u/12v C17, C18? 0180-3441? 270u/25v C52 0180-3443? 560u/7.5v C43 0180-3068? 470u/12v C42? 0180-3442? 1200u/12v AL-ELCTLT Regards, Tom -- This email has

Paul, If you (or someone else) can post the HP part numbers for the capacitors, there is a chance that I may be able to find out what ESR specs were used when the module was designed. Vladan

Rubin - I'd start from the lowbands and work up. +14 from the HI band amp should give you some response but you probably should replace it. You could look at the bias on the FETs in the high band amp

Hi Dave Could you please advise me about which type of Vishay capacitors I should use for the 70900 as I could do with some guidance regarding low ESR how low is low The Vishay capacitors dater sheets

Hi again folks: Looking further, I checked the band 1-3 amplifier, and it doesn't look good: the output must be +26 dBm and I only read +14.x, which is the output I measured in the the A16

RubenRubio - Sounds like it is defective - be sure to check the output of the 3.8G oscillator. The low band amps are available on e-bay, just be sure to check it as soon as you get, and run it in your

Definitely look at the column of electrolytic capacitors in the middle of the power supply board. It seems most 70900s have succumbed to failures of those capacitors now. There have been YIG failures,