Lokking for Service Manual HP 6965A Powersupply - Page 1
Forum section: electronics / repair

author: fossi
author_rank: Contributor
timestamp: November 27, 2015, 04:27:28 pm
content: Hello,I am looking for a servicemanual for a HP Powersupply 6965A.It might also be possible, that this powersupply was manufactured from Harrison and sold under the name of HP.All the transistors and or thyristors on the heatsink were missing.It has a preregulation with scr.Perhaps someone can help me with a schematic diagramm or servicemanual.Thank you in advancefossi

author: joshforester
author_rank: Contributor
timestamp: November 29, 2015, 05:17:48 pm
content: Seems like it might be a slightly modifiedHarrison LVR with HP branding as you suspected. Very hard to find this model number in particular.Maybe one of the 6434b or 6296A manuals could help (not sure how much changed between these models and the one you have.) Worth a shot!http://bama.edebris.com/manuals/hp/

author: oldway
author_rank: Super Contributor
timestamp: November 29, 2015, 07:33:07 pm
content: In my opinion, it is probably the same or very near schematic as HP6291A.Service manual can be downloaded on Keysight technical support page:http://www.keysight.com/main/techSupport.jspx?cc=BE&lc=dut&nid=-536902299.536879791.08&pid=1000001538%3Aepsg%3Apro&pageMode=OV

author: fossi
author_rank: Contributor
timestamp: November 29, 2015, 08:11:55 pm
content: Thank you for the hints.Before I started the thread here in the eevblog, I have already found these sources, but not the correct manual or schematic. I think it's not easy.I have downloaded the manuals and found out:the 6434 has the regulation with scr's on the primary side of the transformer. The mine is on the secundary side. This will not fit.the 6296 is more similar to my powersupply.the 6291(0-40V, 5A) is similar to the 6296 (0-60V, 3A) and has the same preregulation with scr.I will try to compare it with my hardware and hope to find a possibility to repair it.

author: oldway
author_rank: Super Contributor
timestamp: November 29, 2015, 09:05:31 pm
content: the 6291(0-40V, 5A) is similar to the 6296 (0-60V, 3A) and has the same preregulation with scr.Yes but SCR's and power transistors are perhaps different as output voltage and current are not the same.

author: fossi
author_rank: Contributor
timestamp: November 30, 2015, 04:08:42 pm
content: @oldway:I agree. But for this reason, I am looking for the manual, schematic or only a partlist.My problem is, when I purchased this powersupply (it was cheap), the transistors and or scr's on the hetasink are missing and no hint, which parts have to be installed on it.regards fossi

author: oldway
author_rank: Super Contributor
timestamp: November 30, 2015, 04:34:24 pm
content: HP6291A has only one pass transistor TO3 NPN with beta = 35@4Adc (Vbe is not specified but 100V is enough) and a driver TO3 transistor of the same type. (ref. HP : 1954-0225)The two SCR's are TO3 8A 200V 2N3669 RCA.

author: Kleinstein
author_rank: Super Contributor
timestamp: November 30, 2015, 06:29:47 pm
content: Once you have the circuit diagram one could find a suitable transistor. This might not be the old original one, but a more modern type.

author: fossi
author_rank: Contributor
timestamp: December 16, 2015, 10:02:38 am
content: Quote from: Kleinstein on November 30, 2015, 06:29:47 pmThat's my problem. It seems nobody can help me with a circuitdiagram or servicemanual.

author: fossi
author_rank: Contributor
timestamp: March 07, 2017, 03:26:10 pm
content: For this powersupply 6965A I am looking for a transistor and still a circuit diagram..The transistor is marked GT2555The only thing I can find in another manual is:it must be a pnp germanium transistor in a metall TO-5 housing.Does someone have data of this type or know a similar transistor for replacement.Thank you in advanceFossi

author: dacman
author_rank: Frequent Contributor
timestamp: March 07, 2017, 11:46:59 pm
content: Being made of germanium, I would assume that it would not be a high voltage nor high power part. Do you know how much voltage it would need to handle? Is there another one that can be tested? My guess for a cross for the GT2555 is an NTE100.

author: amspire
author_rank: Super Contributor
timestamp: March 07, 2017, 11:57:26 pm
content: Was the GT2555 just a 2N2555 made by GE? I have the GE transistor book somewhere.The 2N2555 was a 100V 3A Germanium PNP.

author: amspire
author_rank: Super Contributor
timestamp: March 08, 2017, 12:27:27 am
content: A company that made transistors (might be Triacs) beginning with GT was Hutson Semiconductors, but I have never seen datasheets from Hutson. Hutson was a researcher from Bell Labs. Hutson Semiconductors became Hutson Industries and finally closed in 2014.GE made transistors beginning with GET, but I cannot find a mention of GT. The GET transistors were GE versions of the 2N transistors - eg a GET2222A and a GES2222A = 2N2222A

author: dacman
author_rank: Frequent Contributor
timestamp: March 08, 2017, 01:01:43 am
content: A cross for the HP 1850-0169 (GT2555) is supposed to be a Keysight/Agilent/HP supplied SA3011 or Texas Instruments GA3114. It's a PNP germanium small signal 150mW metal common collector transistor. General Semiconductor is listed as the supplier for the GT2555.

author: fossi
author_rank: Contributor
timestamp: March 08, 2017, 04:02:53 pm
content: Thank you so far for the hints, where I can search for.Enclosed a picture, which may help to identify the company. I don't know this sign.regardsfossi

author: olliisit
author_rank: Newbie
timestamp: March 08, 2017, 07:56:57 pm
content: Company should be:General Technology Corporation