Quote:
Originally Posted by andy
When replacing caps, I generally look for low ESR and high ripple current. It's generally the heat generated inside the caps that causes the most damage.
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Generally yes - but not so for the C621 in the PC chassis. One look at it's location and you'll see why - placed about a mm off of a large heatsink, just baking, and with a 42V vertical (ramp) signal placed on the cap - 50V was marginal, and the original was already a 105 degree cap - back then, there were no caps marketed for Low ESR or for high ripple current. The blue sheet with the GE replacement walked you through a GE engineer's explanation about capacitance change (they generally lost about 50uF, along with an ESR jump above 3 ohms) and external heat - and about 4 years late...
PC chassis sets were the only ones we didn't seek warranty reimbursement for the replacement caps - the caps that GE supplied were the same 50V Marcons for about 3 years, and we knew they wouldn't last, so we ordered up a bunch of 105 degree 100uf/100V Panasonics from Digi-Key at 13 cents a cap in 100 quantities, and had to restock several times - so we probably saw 200-300 of the sets. GE finally replaced the cap with a 100V one(also a Marcon 105 degree), but it took about 3 years after the warranty period was over.
Out of warranty repair was $25.80 - 24.50 labor, plus the cap and tax. We could quote an estimate at the front counter on PC-chassis sets. GE reimbursed us about $17.00 per set for warranty repairs, and we did about 50-60 sets. Filling out the forms took longer than the replacement of the cap and a burn-in run. Two weeks later, here comes the payment from GE. Most sets failed outside of the warranty period. Fun times - like money on the street, just waiting to be found!