My (used) E3610A PSU has wrong comps. in it. - Page 1
Forum section: electronics / general

author: bingo600
author_rank: Super Contributor
timestamp: June 11, 2012, 05:32:20 pm
content: Followup from herehttps://www.eevblog.com/forum/general-chat/advice-hp-e3610-vs-hp-6236b/I got the E3610 from the Ebay seller , and i bought it as defect.But this is not good.I allready got a bad taste when i received it , and discovered that the Current Pot was single turn.Now i have had the time to open it.I just opened it , and was quite surprised and sad ......Either this is a super "HP Proto" , or a very bad diy fix.Code:Comp Item- Org Value- Inserted value - Pict - Comment----- ------------------- --------------------- ----------------- -------- ----------------------------------R19 CC frontpanel Pot - 10 turn 10k- 1 turn 10K - 12 + 15 Will replace with a 10 TurnU2 12v Regulator - MC7812CT - LM340T12 - 16 Might be OKU4 Current OpAmp - LF442CN - LM1458N - 18 I think this is a bad oneU5 CC/CV Indicator - LM393CN - LM393N - 20 OKU1 Voltage OpAmp - LF411CN - LM741EN - 21 I think this is a bad onePCB PCB number - ?? - 23 Wonder if this is a 3610 PCB ?C7Pos. REF CAP - 330uF 50v - 330uF 50v - 25+31+33 Might be leaking (Change)C13Neg. REF CAP - 470uF 50v - 330uF 50v - 26 + 27 Might be leaking (Change 470uF)

author: bingo600
author_rank: Super Contributor
timestamp: June 11, 2012, 05:36:40 pm
content: More pics

author: bingo600
author_rank: Super Contributor
timestamp: June 11, 2012, 05:43:49 pm
content: I will prob replace the Opamps & Comparator and C7 + C13.But what should i get for C7 (330uF 35v) + C13 (470uF 50V) ?I mean brand ?I would love if someone could point them out @elfa (where i can buy as a private)https://www.elfaelektronik.dk/elfa3~dk_en/elfa/init.do?init=1&shop=ELFA_DK-ENAnything else i should change now that i'm getting parts anyway ?/Bingo

author: T4P
author_rank: Super Contributor
timestamp: June 11, 2012, 06:07:54 pm
content: Basically any brand will do but you can choose epcos, panasonic, nichicon, rubycon, united chemicon these are the good onesJust don't be a stupid arse and do cornell dublier (the price of their caps looks dubious to me)

author: free_electron
author_rank: Super Contributor
timestamp: June 11, 2012, 06:22:40 pm
content: you simply have an earlier revision of this psu. nothing wrong with it.problem is most likely around the capacitors. you see the black traces ? thoses have been eaten by leaking electrolyte.take caps off and measure them out.

author: bingo600
author_rank: Super Contributor
timestamp: June 11, 2012, 06:32:32 pm
content: Update : U3 is a LM329 6.9v Ref , not a LM336 5.0v RefDoes anyone have a schematic of this bugger (i mean this older model ?)/Bingo

author: bingo600
author_rank: Super Contributor
timestamp: June 11, 2012, 06:39:43 pm
content: Quote from: free_electron on June 11, 2012, 06:22:40 pmHopefully i get my Mastec MS5308 LCR Meter tomorrow/Bingo

author: Monkeh
author_rank: Super Contributor
timestamp: June 11, 2012, 06:49:02 pm
content: Quote from: DaveXRQ on June 11, 2012, 06:07:54 pmSome of their caps at least are remarkably durable.

author: bingo600
author_rank: Super Contributor
timestamp: June 11, 2012, 07:02:49 pm
content: Ohh btw:Symptoms now are :Strange numbers in display when cold: -1 in voltage and 0.00 in current.Especially when voltage is turned to max.Gets better when heated up a bit.No difference if i use 8v/3A setting or 20v/2A setting in PSU meter (i can get ie. 13v in both settings) , and maybe 1v diff on output clips.I have measured the Trafo with 3A (12.8 v AC) and 2A (22v AC) , so the 2A/3A switch is doing some stuff./Bingo

author: bingo600
author_rank: Super Contributor
timestamp: June 12, 2012, 07:04:40 pm
content: 2'nd chapter in my repair of the E3610AI have ordered new 105 deg caps , for the PSU.I desoldered the two 330uF-35v C7 & C13.Measured them with my new Mastech LCR meter.C7 was 80uF - 26 OhmC13 was 114uF - 16 OhmCleaned the PCB with IPA & a soft toothbrush.Then i (test) soldered two Panasonic 470uF-25v - 0.04 Ohm Caps in.I have previously measured 16v across the old caps.Now it's regulating , but needs a calibration.I just tried to calibrate the voltage @ the 15v-2A setting.It goes ok , but the PSU meter is EXTREMELY temperature sensitive , with the lid off.It shifts 1.5v up , if i just blow on the PCB.And if i put my finger on R17 (900K , and part of the voltage divider for the PSU meter) , it really wanders upwards.At the same time the output voltage is still stable , and doesn't wander (measured with my 34401A)I will prob change the Current pot to a 10K - 10-turn , if i can get the ones i have to fit.And then i'll try to calibrate the current first , and then the voltage./Bingo

author: bingo600
author_rank: Super Contributor
timestamp: June 12, 2012, 09:09:52 pm
content: Update ....A good EE friend of mine , meant the "Ultra sensivity" on the PSU volt meter (R17).Might be due to still more "Electrolythic gooo" around the "Meter divider resistors".And after a 2'nd IPA washdown , and a resoldering of all the resistors there ,on the topside (i had resoldered them on bottom). It now seems very stable ... And follows the 34401A quite nicely.Damm that board needed a serious cleanup.Now on to the Current Pot and a full calibration.Btw: Does anyone have an idea if i should implement the "Servicenotes" , or is my PSU too old ??I would prob do the 330 / 470uF (C7 & C13) mod (overshooting) ... But the rest ??/Bingo

author: free_electron
author_rank: Super Contributor
timestamp: June 12, 2012, 10:25:56 pm
content: ah yes.. electrolyte is conductive after all... very conductive, and acidic too...you could easily implement all the mods of the servicenotes. there's about 6 or 7 i believe.

author: Unknown
author_rank: Unknown
timestamp: June 12, 2012, 11:24:35 pm
content: Quote from: bingo600 on June 11, 2012, 06:32:32 pmHP usually includes a backdating section in the back of the manual that indicates changes for older serial numbers. I haven't checked the E3610A manual whether it includes a backdating section.

author: bingo600
author_rank: Super Contributor
timestamp: June 14, 2012, 04:08:32 pm
content: Quote from: alm on June 12, 2012, 11:24:35 pmThere is nothing in the manual.But today i got a hint that the E3610 was officially introduced in '92 , and the comps in my vers is 91's , indicating it might be a very early model (or even a proto)./Bingo

author: bingo600
author_rank: Super Contributor
timestamp: June 16, 2012, 10:18:39 am
content: Update ...I'm still waiting for the 330uF Cap (to fix overshoot) , so now i still have 470uF in both C7 & C13.But the PSU seems to be behaving ok ....I decided to do the calibration.I knew that Joe Geller from GellerLabs had a HP 6632B PSU , as he told me how to use it as a LOAD.So i asked Joe if i could calibrate the E3610A using just my 6632B.Joe send me a nice description , and it was real easy.To use the HP 6632B in Load/Dump mode.Set voltage to 0.Then just set the current to the desired Load.A super featue is that the 6632B Volt/Amp meters , will still display the voltage (measured) and current (dumped) on the output connectors. So you have an inline Volt/Amp meter on the "jacks".So i just set the E3610 to 3A(mode) full voltage & amps, set the 6632B to 0v-3.5A , and adjusted R31 to 3.15AmpAdjusted R3 to show 3.15Amp , pressed CC and adjusted R19 to show 3.15AmpThen set the E3610 to 2A(mode) full voltage & amps , set the 6632B to 0v-2.5A , and adjusted R32 to 2.10AmpRemoved the E3610A wires from the 6632B , and connected them to the 34401A.Dialed the PSU voltage until the DMM showed 15.002v , adjusted R20 until the PSU display showed 15.00v.Job doneNow i'm quite sure i have a working E3610A , and i'm just waiting for components to implement a few of the servicenotes.Thanx to everyone that have contributed to my "Repair & Calibration Quest"/Bingo

author: free_electron
author_rank: Super Contributor
timestamp: June 16, 2012, 01:25:14 pm
content: 6632 has the downprogrammer on board so you can indeed use it as a load. But dont overdo it....

author: bingo600
author_rank: Super Contributor
timestamp: June 23, 2012, 04:29:00 pm
content: I finished my repair.Replaced C7 with a 330uF 63v , and C13 with a 470uF 63v. - Repair & ServiceNote-2 (SN-2)Desoldered C4 & C5 SN-4.I'm missing comps (tantal) for SN-3 but i might just wait and see if i have that problem.Now the E3610E from 91' week 51 is still going strong again./Bingo

author: muvideo
author_rank: Frequent Contributor
timestamp: June 23, 2012, 04:54:23 pm
content: Quote from: free_electron on June 16, 2012, 01:25:14 pmNow this is worrisomePlease can you be more specific about this? I use often the 6632 as load, will I incur in problems?Thanks,Fabio.

author: SeanB
author_rank: Super Contributor
timestamp: June 23, 2012, 05:01:24 pm
content: He means don't exceed the voltage and current maxima, as too much heat dissipated in the load can cause damage and burn out components. The limits will be defined along with length of use in the manual somewhere.

author: free_electron
author_rank: Super Contributor
timestamp: June 23, 2012, 07:56:42 pm
content: what i mean is that the downprogrammer is only for the given output voltage / current of that supply !so dont start using this as a dummy load at 120 volts for example. you are going outside the range of the supply.the downprogrammer is only working correctly if you stay inside the limits. the limit may actually be less than the supply. read the manual. there will be a section about it

author: muvideo
author_rank: Frequent Contributor
timestamp: June 23, 2012, 08:23:38 pm
content: Ok, thanks for the explanation, I feared of some known weakness.The limits are stated in the instructions, it's a two quadrant andsymmetric current wise.The problem can be the crowbar in case of overvoltage.Fabio.