D9200 out :(

[Madman]

I have a D9200 that is once again dead... its old but has LESS than 50 hours on it... (I know that doesn't mean to much)

Anyway the unit had sat for a year or so unused (in the cab of course) Went to turn it on and nothing....
I checked the common things on the troubleshooting  list (HOT section) and and few things John @ WG has suggested.

I get a real faint (very faint) relay click then nothing... dead no raster, no HOT.. Any thoughts.....  ?

Thanks in advance.....
Dan

[Ken Layton]

Wells used crap capacitors in many of their late models like yours. It would be a good idea to recap it then see what it does. You've got what is probably Wells-Gardner's most troublesome monitor.

[Madman]

Thanks ken... I ordered the cap kit.. I'll dig through this one way or another and report back what i find...
I somehow suspect its not a cap but figured I would do it since the whole thing including the tube needs to be removed from the cab for proper troubleshooting. I'll start by isolating the supply and testing the 170 line...wish me luck.

[Madman]

I think I will document my repair as much as I can to POSSIBLY help another person.. I have been reading alot on this GEM of a monitor and will try to collect the data here.

Problem:
Set is DEAD only a faint relay click can be heard.
I called WG and (John) gave me a list of components to test. I decided that the 20 they cost would be worth it to just replace as I have not repaired a TV or such in a very long time and have long since forgotten how to properly test some components..

(REPLACED)Q401 TRSTR NPN KSC1845-F 086X0385-001
(REPLACED)Q425 TRSTR NPN 2SC4770 086X0392-001 NTE2324
(REPLACED)Q418   TRSTR NPN 2SC5144 (TOSHIBA)
(REPLACED)413   FET IRF644A
(REPLACED)414   FET 2N7000
(REPLACED)d424   DIODE 1N4148

(tested good)r462
(tested good)r854

ok... same results.. (hehe I now have spares of those parts....)
OK... no chance in a freebe... I was trying to avoid taking the tube out of the cab.....

Now I am pissed//<< but will have fun defeating this thing!

Ordered a cap kit (just in case)
Ordered a cap tester
Ordered a High voltage probe....

First order of business will be to isolate the power supply and test voltage and waveforms (my scope will get some use).
Disconnect r854 put 120 light bulb at supply side and to cold ground.

To be continued after I remove said monitor from cab...................

[qrz]

what's the raw B+ across BD801 - 240Vdc or higher ?
for input voltage below 130Vrms , the STR83145 switches the input to function as a line doubler
above 170Vrms, it switches to fullwave rectification   
see:   http://pdf1.alldatasheet.com/datasheet-pdf/view/55222/ALLEGRO/STR83145.html

the faint click might be the degauss relay attempting to toggle at less than rated 12v

[Madman]

Ok first bad part

R804 is open... all diodes in the supply side are good and all power resisters have been checked so far...

I did find STR83145 on ebay for 5 bucks so I may order one just in case..

[Madman]

After speaking with John at WG again I have ordered a replacement STR8314.. 2 bucks not bad....
I also received the cap meter so I will be checking caps like mad tonight!!

[lilshawn]

I also received the cap meter so I will be checking caps like mad tonight!!

please note: (depending on the ESR meter)

often with caps in power supplies and whatnots, they will place 2 or more in parallel with each other. if one is bad, and the other is good, the ESR will say it's good (electricity takes the path of least resistance)

likewise 2 marginally good caps will each measure good since the total resistance is divided by the caps.

read read then read again the instructions provided with your meter, you will save yourself lots of time in the future.

[Madman]

Thanks for the advice! Looks like I'll remove the caps to check as there is only a few of them///

UPDATE:
Its alive!
Its now a clicker! I will try to isolate the supply tonight to pin down the shutdown problem...
Hopefully I'll receive my caps today so I can just replace the PS section!

[Madman]

Ok... this is what I know so far...
Replaced R804
Set came on for a sec then went to click mode...
Rechecked HOT (it was replaced even though it seemed good) It still checks good.
Checked D417 (I forgot to check this before.. mad @myself) it is shorted.....bummer

Checked R854 again.. it is open now, was not before.

Checked power supply with light bulb load seems fine 170V steady...

To do:
Replace R854
Recheck entire HOT area AGAIN.........
Check rest of voltages tomorrow
Wait for new damper diode to arrive....
Rapcap when caps arrive....


Pray its not the flyback killing parts?
What could cause the damper to short? Age, bad flyback?

[lilshawn]

A bad flyback is a definite possibility. I wouldn't rule it out, but I also wouldn't jump ship on it yet either.

But do check and recheck everything... Sometimes not fixing one thing will cause something else to fail. With these chassis, it seems like all sorts of things go wrong with them.

Seems as though you have to get this thing 100% before putting the juice to it, or it blows a bunch of parts out in the process.

[Madman]

Its the waiting game now....(10A damper diode from BD enterprises) John from WG is on the flyback is good fence.... whats the best way to test a flyback?

I also received the cap kit from Zanen Electronics.... Everything looks good but the big power caps were not included... Mine are not bad so I am not stressed about it... If I am not to tired I'll do the HOT side of the board tonight...

[lilshawn]

whats the best way to test a flyback?

honestly? i have no idea. i've never had to test one. they have always just worked, or obviously failed (burned holes in case)

my best guess would be to do a resistance test throughout the pins... if there is any 0 ohm readings between any pins my guess it would be bad.

it would be good to test the new one and compare it to the old one though...

[grantspain]

i had a d9400 flyback go,customer reported burning smell and when i checked the chassis I found a 2sc5387 and a irfs634b both short circuit.I replaced them both and it fired up with a picture for about 30 secs and blew both again and red hot.
Flyback had no obvious signs of burns but i changed it anyway along with the other 2 components and hey presto all up and running

[shagster]

Its the waiting game now....(10A damper diode from BD enterprises) John from WG is on the flyback is good fence.... whats the best way to test a flyback?

http://www.electronicrepairguide.com/testing-flyback-transformer.html

[Madman]

Ok, I am a bit closer...

The set now powers with a picture but my horizontal is stuck at around 5 inches or so... everything else seems fine colors are good and the image is stable...
I have control over all perimeters but horizontal is just small......

could Q411 cause this? can IC 404?
Thoughts?
Thanks!

[Madman]

It lives.......
Thanks for everyone's help!

I'll post up the sequence of events for the next person that lucky enough to attempt repair of one of these.... i am tired for now...

[Ken Layton]

Glad you got it running. This model can be very time-consuming to repair.

[Madman]

Thanks ken....I have about 3 1/2 solid hours in it... I thought about having WG do it but figured I better learn myself if they are problematic.

Here's the log:
1.) It was dead (faint click)<<< must have been degauss relay not fully powering
2.) checked the following items: (and replaced JUST in case)
(REPLACED)Q401 TRSTR NPN KSC1845-F 086X0385-001
(REPLACED)Q425 TRSTR NPN 2SC4770 086X0392-001 NTE2324
(REPLACED)Q418   TRSTR NPN 2SC5144 (TOSHIBA)
(REPLACED)413   FET IRF644A
(REPLACED)414   FET 2N7000
(REPLACED)d424   DIODE 1N4148
3.) Checked power supply and found R804 to be open and replaced it
3.) Set then powered on for a sec and when into protection (click, click, click)
4.) Realized I forgot to check D417
5.) D417 was shorted so I replaced it.
6.) I found that powering the set with D417 shorted and R804 replaced caused R854, R462 and Q413 to be damaged.
7.) After replacing the above the set powered on with a 5 inch horizontal...
8.) After going over the unit again I decided to pull Q414 and compare with a new and found it to be bad as well.
9.) After replacing Q414 again...set then powers on fine.
I have learned a lot from this repair and expect WHEN it happens next time to cut the repair time in half and hopefully replace only the parts needed.

I also bought a capkit but have not used it yet... I did check a few caps here and there as per the suggestions but found nothing close to bad... This makes sense as the set has less than 50 hours on it..  
The other thing that made this difficult is I did not remove the tube from the cabinet as it is a royal pain to do so and I am lazy.... I basically troubleshooted it un-powered...  I fully realize this is NOT the best and most efficient way to do it but hey... I got lucky!

Thanks for the help!
 

[VidEng]

Thank you for posting your troubleshooting experience. 

My D9402 went out too, and after reading your post I checked R804 and it was open.  I'm replacing it with a higher-wattage version; hopefully it can take the strain better.

I am using it in a MAME machine and while the PC boots up, it goes through a lot of different display modes which makes the monitor re-adjust itself and there is a lot of relay clicking and such.  I'm putting in a time-delay relay to make the monitor power up after the PC has been on for 20 seconds.  Might reduce wear and tear on the monitor.

-James

[lilshawn]

I checked R804 and it was open.  I'm replacing it with a higher-wattage version; hopefully it can take the strain better.

stuff don't blow up for no reason. you need to find the source of the excess load in the circuit being powered on the other side of that resistor. in this case, simply replacing it with a bigger wattage resistor is akin to replacing a constantly blowing 5 amp fuse with a 30 amp one....sure it will work...until it doesn't... and takes out everything else.

[VidEng]

Good point.  I will check downstream components in addition to D417 which tested good on mine.

BTW I have already done a full capacitor renewal on the deflection board and the neck board.  Hopefully can extend the life of this monitor.

Thanks,
-James