dead WG 25K5515 (medium res) in my 720°

[gwarble]

monitor gets 120, no glow

fuse is blown (big one on the left side of chassis) but HOT does not test shorted... so that would lead me to the flyback? should i start by just changing the fuse (or putting in a breaker for testing) and see if it was a fluke/environmental? or does that fuse being blown automatically mean a problem with another component...

i have parts on the way, but the more i can learn the better, thanks for any tips
- gwarble

EDIT: my bad, fuse is not blown... investigating ic501/c507/B+ per flowchart...

 

[modessitt]

I think you can get a flyback from Arcadecup if you need one, but they don't go bad very often.

Troubleshoot this like a K4900. There's a flowchart somewhere. I think the B+ is slightly different, but not much (maybe 7vdc). It needs an isolation transformer, so check the rectifying diodes and VR first. If any are blown, that would blow the fuse...

 

[gwarble]

thanks, yeah i've been trying to connect the dots with the 4900 being similar...

BUT...

i was wrong, the fuse is not blown... so i'll proceed with the B+ checks and that section of the flowchart after dinner and post my readings if i don't get anywhere

thanks
- gwarble

 

[gwarble]

155vdc is the current B+
166vdc measured on the far end of R503

IC501?
C507?

thanks

 

[tron guy]

http://www.ebay.com/itm/WELLS-GARDN...201?pt=LH_DefaultDomain_0&hash=item53e7179221

flyback can be had here as well if chad doesn't have it.

 

[gwarble]

thanks for the link... i'm hoping its not actually the flyback, fuse is actually intact, HOT isn't shorted...

but good to have a source if need be


so would a high B+ put it into shutdown? (155vdc)
anyone know what it should be on this monitor, k4900's flowchart says 130vdc, modessit says its different by about 7 volts, which way? anyone know? image shows 123 and 159 being two voltages present on the ic501... but how do i know which is B+ if any

i'm waiting for a cap kit, so that seems like the next logical step, but maybe i should check ic501 while its pulled apart...?

thanks again

 

[modessitt]

I think the 5515 is 123, but I might be wrong.

Anyway, start with the cap kit and go over the entire thing for cold solder.

High B+ WILL put it into shutdown...

 

[gwarble]

cool, thanks for the tips...

no visual signs of problems (caps, flyback, board, etc)... screw in horizontal width coil is exposed from the top of the white plastic by about 1/4", or 5 threads or so... is that normal? i'm used to them being subflush... otherwise everything looks clean, we'll see what the cap kit fixes...

if its just C507 that's usually the culprit i could just swap that out tonight and see before the kit comes... though i'm feeling lazy...

thanks again
- gwarble

 

[modessitt]

It's probably a combination of caps and solder...

 

[gwarble]

yeah i hope so...

str381 case measures 165 and HOT case 156vdc

should i swap the voltage regulator while its pulled?
thanks
- gwarble

 

[gwarble]

hmm... manual says ic501 is str380... the one in there is an str381... is that an ok replacement?

reliable previous owner said it was cap kitted and transistor'ed in about '96, and ran fine until turned off over a year ago... powered on to sell it and monitor's dead

so i doubt its an incompatible part, but worth noting
- gwarble

 

[modessitt]

Um - I have a 5501 that required an STR380, and took a while to find, as the STR 381 did not work as a replacement.

Since the manual specifically says STR380, I'd put one in. I got mine from www.electronix.com Not sure if they still have any. You might check with Bob Roberts, too...

 

[paul400]

i didnt see any str380's on bobs website, but i did just pick up three of them from Electronix. so yes they still have them.

 

[arcadecup]

the 5515 flyback, which you need does go bad often. I do have replacements now on my website for $33.00 shipped. you want 053X0531-001. I am the original catalyst for these to even exist in the market along with many others in the first place if that means anything to you.

I see twisted also carries the 6100, amplifone and SANYO ezv. Glad to see others jumped the band wagon to carry these after I was the only one who had to balls to put a end to what I seen as a big price collusion skit that many of the klov users fell for.

Ignore the resistor in the picture thats not needed for the flyback install. that was a earlier version of the flyback that produced a lower heater voltage.

 

[arcadecup]

if your reading a b+ on the hot it's not pulsing which means it's not because its missing the 25khz drive needed at the base of the hot or the flyback is shot or the yoke is disconnected / open. I would go with those reasons first before others.

 

[gwarble]

Thanks for the tips, how would i go about check the 25khz drive to the hot? Or what supplies it?

Its also in shutdown with such a high B+, would that stop the pulse?

 

[2600]

Ignore the resistor in the picture thats not needed for the flyback install. that was a earlier version of the flyback that produced a lower heater voltage.

For those of us that have the earlier version, should we return them for a newer version? Did you experience any problems with the earlier version?

 

[gwarble]

Arcadecup: thanks for the info, so they do fail often? Should i put in a new one and switch the str381 with a 380?

Someone suggested it may have been swapped if the picture was too small (going up to the 130v str381)

 

[SuperSprint]

My 19" K4915 is an STR380. IIRC, on the K4915, the STR380 is used for 19" (123v B+) and the STR381 for 25" (130V B+). Check your B+ test point and use the correct VR for your unit.

 

[arcadecup]

Absolutely, anyone may do so. however I don't think I sold more than 10 of the old style and sold them with the resistor change. you would have to check the manufacture date on the small sticker hiding behind the ferrite. i pitched all the old ones years ago.

For those of us that have the earlier version, should we return them for a newer version? Did you experience any problems with the earlier version?