Electronics > Repair
HP 53310A - Power supply troubles
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kj7e:

--- Quote from: m3vuv on December 05, 2021, 11:19:32 am ---dont you think im already doing that?,how about you read the question i asked before posting FFS!!

--- End quote ---

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 (8) 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 ?
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