Bonehead Sanyo 20EZ Thankgiving blowout

Torin

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Well, I deserve a swift kick in the arse for this one.

Recapped a sanyo 20EZ and replaced IC601. Got it back in the monitor and hooked up everything including a multimeter to the B+ test point and set the multimeter to 200VDC. Unfortunately, I plugged the red lead into the wrong multimeter socket (the ohms socket) by mistake and flipped the power on, it fried something on the chassis. The large fuse 4A 125V blew as well as the fuse by the power cord in the nintendo cab. Replaced these and it still won't power up. Now what? From the flow chart, it says to test D601-D604. Forgive my rookie questions, but how do I do that? Do I do that with the chassis out and unplugged? What setting do I put my multimeter to? Any other ideas? Thanks for the help and I'm sure you got a laugh outta this one.
 
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well first off a sanyo's B+ is only 108vdc. so you are probably in HV shut down.

and to test a diode use the diode mode on your meeter. you should get continuity on way and not the other. or a beep if your meeter has that option.

if you cant get a reading in circuit pull one leg and test again.

Peace
Buffett
 
well first off a sanyo's B+ is only 108vdc. so you are probably in HV shut down.

and to test a diode use the diode mode on your meeter. you should get continuity on way and not the other. or a beep if your meeter has that option.

if you cant get a reading in circuit pull one leg and test again.

Peace
Buffett

Sorry, I meant that I set the Multimeter to 200VDC before powering up.
 
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There is another fuse on that chassis. F301(.3A / 300mA) I believe, near IC601. Also check Q901 current limiter, I have seen that get shorted when the fuses have been blown. Q901 is also located near the IC601 voltage regulator.
 
The diodes D601-D601 all give a reading around 650. I tested the HOT and it reads around 1700. When I test it, it gives a quick reading and then quickly goes back to 1. I have to re-test to get another quick reading. Is that normal? I've checked both fuses. Any other ideas what to check?
 
no the H.O.T. should around .470ish on both legs.
black lead on the outer case.
and red on each leg.
if it reads a 1 it is probably shorted.
remove it and test again.


the diodes should read around .488ish.
black lead on the end with the stripe.
read lead on the non striped side.

Peace
Buffett
 
no the H.O.T. should around .470ish on both legs.
black lead on the outer case.
and red on each leg.
if it reads a 1 it is probably shorted.
remove it and test again.


the diodes should read around .488ish.
black lead on the end with the stripe.
read lead on the non striped side.

Peace
Buffett

Ok, the diodes are all about 508

The HOT is 551 on both legs.

I appreciate the help.
 
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http://www.youtube.com/user/randyfromm#p/u/61/wFHAGd_Tcvw

Here is a quick video for testing semiconductors. He stresses testing not only base to collector and base to emitter, but also testing emitter to collector.

The Q901 I tested desoldered from the chassis was testing good base to collector and emitter, but shorted from emitter to collector. It was causing my monitor to go into HV shutdown.

Are you getting any B+ reading at all? Or completely dead?
 
Thanks for the helpful link. The board has no B+ and is completely dead.

I get a reading on the HOT of 551 on both legs


http://www.youtube.com/user/randyfromm#p/u/61/wFHAGd_Tcvw

Here is a quick video for testing semiconductors. He stresses testing not only base to collector and base to emitter, but also testing emitter to collector.

The Q901 I tested desoldered from the chassis was testing good base to collector and emitter, but shorted from emitter to collector. It was causing my monitor to go into HV shutdown.

Are you getting any B+ reading at all? Or completely dead?
 
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Q901 reads 656. if that is on both legs then that is fine.

the H.O.T. should around .470ish on both legs. they are side by side in the middle if the transistor. with the solder on them.
the two outer legs top and bottom are are the screws that hold it to the heat synk.

Ok, the diodes are all about 508. that is ok they are fine.

Peace
Buffett
 
Q901 reads 656. if that is on both legs then that is fine.

the H.O.T. should around .470ish on both legs. they are side by side in the middle if the transistor. with the solder on them.
the two outer legs top and bottom are are the screws that hold it to the heat synk.

Ok, the diodes are all about 508. that is ok they are fine.

Peace
Buffett

Thanks for the clarification. The HOT is testing 550 on both legs.

Q901 is 621 on both legs.
 
OK that's good. sounds like all the parts tested so far are fine.

did you test all 4 diodes 601-604?? they should all read close to the same.

after that i would center the B+ pot replace all the fuses and try again.

Peace
Buffett
 
OK that's good. sounds like all the parts tested so far are fine.

did you test all 4 diodes 601-604?? they should all read close to the same.

after that i would center the B+ pot replace all the fuses and try again.

Peace
Buffett

The diodes are all around 580 - 600

I will replace fuses and try again. Thank you.
 
Ok, I replaced the fuses and found a loose fuse holder. I fixed that and now the monitor fires up and there are some green dots on the screen that fade. The B+ is at 142 and will not adjust. Any ideas? Maybe I blew the flyback? Thanks again for the help.
 
ok keep it off till you can adjust the B+.

i have yet to replace a fly on a sanyo. they can go bad but i have been lucky i guess.

your IC601 is probably shot. and there is no way to test it.

is your B+ pot the shitty metal one?? if it is replace that POS. a 5k or 10kwill work.
i use the 10k and have no issues.


buy from riptor his parts are excellent.
https://www.twistywristarcade.com/search?orderby=position&orderway=desc&search_query=la5112

and see if your local store has the pot.

replace theses and try again. they are the next possible parts i would try. i have not had to do much else to get a sanyo back running. that a high nonadjustable B+.

Peace
Buffett
 
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I just replaced the B+ pot, the B+ filter, Q901 and the IC601. Could this surge have fried the IC601?

When I installed the IC601 that I just ordered from Riptor, I lined up the circular notch on the chip with pin 1 on the chassis. I think that was the correct way. Any advice here? Thanks again buffett!



ok keep it off till you can adjust the B+.

i have yet to replace a fly on a sanyo. they can go bad but i have been lucky i guess.

your IC601 is probably shot. and there is no way to test it.

is your B+ pot the shitty metal one?? if it is replace that POS. a 5k or 10kwill work.
i use the 10k and have no issues.


buy from riptor his parts are excellent.
https://www.twistywristarcade.com/search?orderby=position&orderway=desc&search_query=la5112

and see if your local store has the pot.

replace theses and try again. they are the next possible parts i would try. i have not had to do much else to get a sanyo back running. that a high nonadjustable B+.

Peace
Buffett
 
yes that was correct.

yes it could have smoked it. do you still have your old one. if so you could swap it in and see.

if IC601 and or Q901 are faulty in any way your B+ will not adjust.

did you put the mica insulator back behind Q901 seems like you did or it would have shorted out.

also check and make sure you don't have a solder bridge. i did this once on Q901 and till i un did the bridge i could not adjust my B+.


(just a story.
i had 9 IC601's i ordered from bob i put a socket in one of mine to test them. and all 9 were bad.)

i have never got one from riptor but from what i have heard all his have been good so far. no lemons yet.

so you may socket it so you can test any others you may have on parts chassis laying around.

Peace
Buffett
 
Awesome info Buffett.

Alright update. I have a known working chassis that I swapped out the IC601 from and I got the same result (142 B+ not adjustable). I put IC601 back intothe working chassis and hooked it up to the cabinet and tube. It works and B+ is fine. That eliminates the PS although I didn't think that was the issue.

So, I am thinking I should test Q901 again. I did install it with the insulator and the B+ was adjustable until I blew it.

Well, I have the non-working chassis out. There are three legs to the Q901. Can you tell me the exact way to test it? I just want to be sure I did it correctly.


yes that was correct.

yes it could have smoked it. do you still have your old one. if so you could swap it in and see.

if IC601 and or Q901 are faulty in any way your B+ will not adjust.

did you put the mica insulator back behind Q901 seems like you did or it would have shorted out.

also check and make sure you don't have a solder bridge. i did this once on Q901 and till i un did the bridge i could not adjust my B+.


(just a story.
i had 9 IC601's i ordered from bob i put a socket in one of mine to test them. and all 9 were bad.)

i have never got one from riptor but from what i have heard all his have been good so far. no lemons yet.

so you may socket it so you can test any others you may have on parts chassis laying around.

Peace
Buffett
 
turn the chassis over look at the 3 legs it should say

B red lead here
C black lead here should read.537ish.
E black lead here should read.537ish.

Peace
Buffett
 
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