HP 53310A - Power supply troubles

[kj7e]

dont you think im already doing that?,how about you read the question i asked before posting FFS!!

Well, with that attitude, good luck to you sir.

[Cubdriver]

Th PS on mine has failed as well; it appears that the usual suspects (based on this thread) have been piddling on the board.

To add yet another date point to the thread:

HP silkscreen:
Hewlett Packard P/N 0950-1879

Manufacturer's part label:
Computer Products
XL131-3604E
115/230VAC
220W 50/60HZ
CSA LR50913

Manufacturer's serial label:
P/N: 700040-01
S/N: HHQ 7072
REV: P
DATE: 9143

Agency label:
(None)

Written on PCB:
"79001P REV. P"

Silkscreened on heat sink end of PCB:
"ASSY NO 700040-01 REV" (No rev marking present)

Soldermask marking on back side of board behind T3:
"MC1368B
94V-0
MULTI"

Soldermask marking on back side of board near ( 1000 uF caps and near L4/L6:
"510040 REVD
©1987 9130
PCB information:
"COMPUTER PRODUCTS BOSCHERT INC"

Date code 9118 on Q3 transistor in power supply.

No RIFA yellow capacitors. ALL 1000 uF, 35 V caps exhibit signs of leakage, with corrosion on board.  Remaining caps do not appear to be leaking, but will be replaced regardless.

-Pat

Edit to add - many thanks to KJ7E for the comprehensive BOM - it was most helpful in getting the replacement caps ordered.  Kudos to you, sir!

[m3vuv]

I did make up a lead and fitted a pc atx psu in mine,it sort of half worked but had lots of self test fails,if i remember the 5v rail sagged to about 3.5v,maybe a higher wattage supply would of worked,in the end i recapped the original psu and fitted a metal push button switch on the side of the scope to turn it on or off,i think the people who designed this were on mind altering drugs putting the on off switch at the rear of the unit,crappy design.

[Tomorokoshi]

I finally got around to updating the capacitors. I used kj7e's list. I had been repairing something else, and it had been a while since I used the 53310A, so of course I got all kinds of failure codes and information when I turned it on. There was less and less for the next couple power cycles, so it was clear that it was time to check it.

First I removed the power supply and I connected to the 20-pin output connector to monitor all the voltages. I started with a 40W bulb for the dim-bulb limiter, but I had to switch to 60W. A few were low, and after a couple power cycles it got worse and worse. If I recall one of the 12V rails was having the most trouble. I tried to measure capacitance at the output connectors, but my LCR meter could not settle on a reading.

I ordered the parts from Digi-Key, so in the meantime I removed the old capacitors. Several were leaking and I cleaned up the electrolyte as I could. I only delaminated 3 or 4 solder pads on the top of the board, and none of the tracks delaminated. None of the tracks were corroded enough to require repair.

After installation of the new capacitors I ran it on the bench and monitored all the outputs. It wouldn't run with a 60W bulb, so I switched to 300W. That almost worked, so I ran 60W and 300W in parallel, and that worked. All the outputs were fine, so I reassembled the machine and ran the self-test. All tests are fine, although note that the oven takes a while to heat up enough to pass.

Here are the measurements of both the old and the new capacitors out of circuit. Most were measured at 1000 Hz. The large values were also measured at 100 Hz.

Note: The list from kj7e calls out one of the 2200 µF as C25, while I list it here as C42. The designations on the board are ambiguous in that area.

Ref	f (Hz)	C (µF, old)	D (old)	Θ (°, old)	C (µF, new)	D (new)	Θ (°, new)
C7	1000	866	0.5	-63.4	857	0.386	-68.8
C8	1000	879	0.514	-62.8	851	0.378	-69.2
C9	1000	827	0.47	-64.8	849	0.377	-69.3
C10	1000	856	0.48	-64.3	863	0.373	-69.5
C11	1000	862	0.487	-64	853	0.366	-69.8
C12	1000	850	0.489	-63.9	859	0.367	-69.8
C13	1000	872	0.501	-63.4	861	0.358	-70.3
C14	1000	841	0.477	-64.5	856	0.36	-70.2
C15	1000	851	0.52	-62.5	864	0.359	-70.2
C16	1000	836	0.508	-63	860	0.348	-70.8
C17	1000	355	0.732	-53.8	451	0.205	-78.4
C19	1000	23	2.42	-22.3	43	0.097	-84.4
C22	1000	596	0.408	-67.8	569	0.395	-68.4
C23	1000	600	0.422	-67.1	583	0.37	-69.6
C26	1000	5402	3.27	-17	6414	2.51	-21.7
C26	100	5471	0.384	-69	6283	0.276	-74.6
C27	1000	5203	2.73	-20.1	6652	2.53	-21.6
C27	100	5479	0.329	-71.8	6457	0.276	-74.6
C30	1000	880	0.508	-63	869	0.358	-70.3
C31	1000	826	0.476	-64.5	856	0.351	-70.6
C32	1000	897	0.476	-64.5	861	0.354	-70.5
C33	1000	908	0.475	-64.5	856	0.35	-70.7
C34	1000	190	0.448	-65.8	219	0.099	-84.4
C35	1000	163	0.673	-56	232	0.097	-84.4
C36	1000	177	0.462	-65.2	218	0.097	-84.4
C37	1000	159	1.1	-42.4	219	0.095	-84.5
C38	1000	179	0.536	-61.8	222	0.097	-84.4
C39	1000	190	0.465	-65.1	216	0.101	-84.2
C40	1000	1406	1.93	-27.3	1929	0.711	-54.5
C40	100	1820	0.355	-71.1	1990	0.091	-84.7
C41	1000	1292	2.06	-25.8	1870	0.679	-55.8
C41	100	1760	0.408	-67.7	1920	0.086	-85
C42	1000	1674	1.66	-31	1923	1.41	-54.7
C42	100	1900	0.213	-77.9	1990	0.095	-84.5
C49	1000	5219	2.33	-23.2	6167	2.12	-25.3
C49	100	5367	0.275	-74.6	6345	0.252	-75.9
C50	1000	190	0.476	-64.5	215	0.1	-84.2

                                                   

[artag]

I haven't needed to do this yet but I appreciate the thorough measurements. Useful to get an idea of the health of other units if no leakage is apparent.

What LCR meter did you use ?

[Tomorokoshi]

I used an Agilent U1732B handheld LCR for most measurements. I used an HP 4194A impedance analyzer to check the U1732B and to measure extended frequency ranges. I marked all the parts I removed so I can run a full frequency sweep if needed. C19 and C37 were probably the cause of shutdown, but most of the 1000uF, 35V parts had some leaking.

[Davidthanam]

Hi,
it would be nice if you provide the detail of C43 cap value?
It's a hard time, it burned out, i need to fix it out.
please help me in this regards