Is my converter fried? (TEAR DOWN NOTE)

I took the circuit board off of the metal panel and inspected all of the solder joints underneath. They were all good.

Those big resistors sometimes un-solder themselves. I've resurrected one WFCO converter by resoldering them. Whether or not the slide works without a battery will depend on the specific slide and the rig's wiring. My current slide motor draws a whole 10 amps and as one would guess, runs just fine on the converter only, or without the engine running as the owner's manual requires.

Huntindog wrote:
The PDs are good. I recently replaced my WFCO which never worked right with the Powermax.
I am impressed with it. It actually switches modes right.

Thanks for that. I wasn't really sure which one to buy. I knew I didn't want to go to an 80 Amp because of wire size issues.

DSchmidt_2000 wrote:

Gdetrailer wrote:

ib516 wrote:
They say 10W1K5J on them.

That is a 10W 1K ohm power resistor with 5% tolerance.

1.4K measured using 2K ohm scale of a VOM is within the realm of possibility of being correct since your meter may or may not be able accurately measure that resistance on that scale.

Your resistors are most likely good and not the source of trouble.

Agree that the resistors are good but 1K5J is 1.5K, not 1K 5%. The J might be tolerance if the original manufacturer datasheet is consulted.

:S

Yeah, 1.5K and yes, the J should be the tolerance.. Regardless with those resistors they tend to not go bad and seeing some heated/slightly scorched circuit board under and around them is not uncommon. Pretty typical since the resistor will be dissipating a considerable amount of heat and some of that heat ends up transferring to the wire leads and even the circuit board solder pads..

Used to often have to resolder those on older TVs since the heat build up would often crack the solder joints..

Rarely ever had to replace that style of resistor.

Replacing the caps would most likely make it work again but you would have to nearly replace them all, other wise you will be chasing others which will go bad later on..

OP is on the right track, new convert will solve the problem.

Gdetrailer wrote:

ib516 wrote:
They say 10W1K5J on them.

That is a 10W 1K ohm power resistor with 5% tolerance.

1.4K measured using 2K ohm scale of a VOM is within the realm of possibility of being correct since your meter may or may not be able accurately measure that resistance on that scale.

Your resistors are most likely good and not the source of trouble.

Agree that the resistors are good but 1K5J is 1.5K, not 1K 5%. The J might be tolerance if the original manufacturer datasheet is consulted.

You say the voltage comes up but drops like a rock under load

1: Leave it on charge overnight
2: Measure voltage at teh battery posts themselves NOT the connectors hooked to them, Then measure elsewhere.. I'm betting on one of two things.

1; Surface charge (Won't carry load)
2: Bad connection.

ib516 wrote:
I think one of the biggest issues is good ole Keystone mounting the fan cooled unit in a closed cabinet with absolutely no ventilation. I will add a couple holes once I can find some grates to cut the holes to size.

Yes, electronics don't like to be overheated so anything that will let the air flow better inside the case will be a better situation. IMO, the primary cause of failure is probably due to poor component quality or bad solder conditions on the boards.

I've forgotten which RVnet member repairs these converters but it is probably a simple fix for someone conversant with power supply repair. For that matter, replacing all small components on the boards (if there are no SMD devices) is probably a less than $10 repair.

Good choice on the Powermax replacement, I read good things about the brand.

As a side note, I have given up and bought a new 55 Amp converter from ebay for $110 to replace the junk WFCO 55 Amp unit that came in the RV.

MEXICOWANDERER wrote:
By trying to operate the slides without benefit of the house battery

You officially entered your poor converter

Into a one-legged --- kicking contest

:) It was actually bad before that, it wouldn't even run two LED lights. I have converted all of the interior lights to LED. I tried a lot of things (including the slides), but walking and and flipping on the light switch was first. One set will come on (very dim though), but not two, and again, it doesn't have enough current to operate the LPG leak detector and a set of LED lights as the LPG leak detector goes from green LED to red, to out, when I flip on an LED light switch. Also, it gave me trouble at the end of the season last year - not charging the house batteries, it was just so close to the end of the season, I attributed it to bad house batteries. I had them tested and they were marginal, so I bought new ones.

I think one of the biggest issues is good ole Keystone mounting the fan cooled unit in a closed cabinet with absolutely no ventilation. I will add a couple holes once I can find some grates to cut the holes to size.