skal1

Need help trouble shooting a HP 711A PSU
« on: July 25, 2018, 03:16:31 PM »
Ok ,  had this item for a week or so now  and i can no get it to work as intend ,my first issue is it's missing the relay   K1 from the socket , so if anyone has a HP 711A PSU  who can get me a part number or can source one that would be cool,  the relay is a  potter and brumfield..

cheers


Denis


PRR

Re: Need help trouble shooting a HP 711A PSU
« Reply #1 on: July 25, 2018, 05:40:19 PM »
The power supply will work without the relay. Missing the relay strongly suggests somebody abused it over and over again, so there may be other faults.

Relay was sourced from P&B, which has been through many changes since 1954, and the part-number is clearly an H-P spec number, not any stock P&B relay. It was very likely hand-adjusted to a specific trip point.

Working how it works: In short, an ~18V ~2K N.O. relay which will stand occasional 500V closure at very low voltage. Since that is a very odd part today, we favor a low-cost part so if it fails after some time we do not cry about replacement.

FTR-F3AA018E-HA Fujitsu, $1.38 at Mouser, 500 in stock

http://bama.edebris.com/download/hp/711a/711a.pdf
https://www.mouser.com/datasheet/2/164/ftr-f3ha-318.pdf
https://www.mouser.com/Electromechanical/Relays/_/N-5g31/

skal1

Re: Need help trouble shooting a HP 711A PSU
« Reply #2 on: July 25, 2018, 07:17:02 PM »
hEY thanks  PRR , i think you are right about other faults  though ,  can not get it to go beyond 150v dc,  so i will stripe it down to the three  secondary  windings and go from their.. i will keep you posted gonna need a lot of help with this


cheers

Denis

skal1

Re: Need help trouble shooting a HP 711A PSU
« Reply #3 on: July 28, 2018, 11:25:28 AM »
 >:(  seems that one of the wind are shorted  i can smell the tx cooking , can you still get  a  tx for this, part number 9100-0067,
can anyone help in the usa

cheers

Denis

skal1

Re: Need help trouble shooting a HP 711A PSU
« Reply #4 on: August 01, 2018, 10:46:55 AM »
ok ,found out some info about  who made this tx ,it seems to be PAECO (HP) , so my next ? is do  they have so kind of catology of the transformers they made .

can anyone help with this..

cheers

Denis

radardoug

Re: Need help trouble shooting a HP 711A PSU
« Reply #5 on: August 01, 2018, 10:39:13 PM »
Thats a special transformer in a very old peice of gear. Chances are you wont find one. Options are to get a transformer winder to rewind it for you, or use stock transformers to make up the required voltages.  Are you absolutely sure the transformer is faulty? Disconnect everything from the secondaries and check.

skal1

Re: Need help trouble shooting a HP 711A PSU
« Reply #6 on: August 02, 2018, 07:21:13 AM »
yeah ,tx shot it starts  to  smoke without any load no  rectification ...

@ radardoug ,  the winders  are asking for the current of each winding  and  it is not in the manual , is their a way to calculate these figures

cheers

Denis

radardoug

Re: Need help trouble shooting a HP 711A PSU
« Reply #7 on: August 02, 2018, 06:33:58 PM »
Yes, look at the design and reverse engineer it. Some of the windings are already specified for current. You can make educated guesses for the others. Also if they strip down the old transformer, then they can get the wire gauges and turns ratios. CJ on this forum does it all the time.


 

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