Need some help/guidance trouble shooting SMPS for this tv set.
https://www.badcaps.net/forum/showpo...51&postcount=5
https://www.badcaps.net/forum/showpo...51&postcount=5
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Re: SMPS for RCA 32V434T CRT tv
I blew the fuse while test voltage.
Probe slipped, analog meter fine. Unfortunately, when I replaced the fuse it blew again. Must have shorted something out.
How screwed am I.. uhh, I mean is this SMPS?
Am I
or am I 
?
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Re: SMPS for RCA 32V434T CRT tv
Be glad you didn't
Anyhoos...
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Re: SMPS for RCA 32V434T CRT tv
My bad, forgot thread link.
https://www.badcaps.net/forum/showthread.php?t=16914Comment
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Re: SMPS for RCA 32V434T CRT tv
Found RT860 blown.
It's a thermistor marked 5, 5D210, D V
Will this one from Digikey be an equivalent?
http://search.digikey.com/scripts/Dk...63658373885660
Could this also be the cause of the 5VDC STBY to measure about 42VDC?Attached Filesif you find these attachements useful please consider making a small donation to the site
Last edited by cmj21973; 11-08-2011, 04:32 PM.Comment
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Re: SMPS for RCA 32V434T CRT tv
That thermistor is a PTC type so it *may* be used to limit voltage... Are you sure you're using the right ground for measuring? I've heard of high standby rails but that's out of the norm by too much.
Are the other rails good that come from the same transformer? If they're also very high there's probably something wrong with the opto IC804 or the transistor driving it.A working TV? How boring!Originally posted by PeteS in CAComment
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Re: SMPS for RCA 32V434T CRT tv
Photo #1:
I used the "RED" circled points (photo #1) to measure the 5VDC on the main board. Guess I should have used the "YELLOW" circled points to prevent a probe short.
Photo #2:
I used the "RED" circled points (photo #2) to measure the 5VDC on the Controlboard.
I was retest the 5VDC, with anaolog meter, when I caused a probe short. RT860 PTC could have just finally failed on it own, but I don't think so.
I did remove RT860 and it measures 5.5 Ohms. It also has a chunk if it's encasement blown off.
I didn't get other voltages. Hopefully when I replace RT860 it won't blow fuse, when power is applied, and I can get the other voltage readings.
I thought the tv set had bad caps. Sometimes when it was turned on, it would take a few second to get a pic. Sometimes it would have sound and no picture, but cycling power would correct it till now. I thought it was the flyback until I found the RCA ATC010 Training Manual and start shutdown troubleshooting by testing the voltages.Attached Filesif you find these attachements useful please consider making a small donation to the site
Last edited by cmj21973; 11-09-2011, 01:04 AM.Comment
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Re: SMPS for RCA 32V434T CRT tv
Status:
With a 40watt bulb, across the fuse holder, I determine that D861; D862; D863; & D864 were bad.
I replaced them and retested. IC860 tested bad.
Will be order these to replace RT860 and IC860.
http://search.digikey.com/scripts/Dk...66952994897708
http://search.digikey.com/scripts/Dk...66952994897708Comment
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This relic from a technology path that came to a dead end (but still has historical interest) was brought in with a dead SMPS, which is based around a MK1210 device. I got it going after a battle. It seems to have a strange design - if it's not getting feedback that the secondary is OK it cause the big FET to go into full conduction and overloads resulting in a blown fuse at best or something worse! I'm using a Dim Bulb Tester (70W/230V) which thankfully has saved the day a number of times whilst repairing.
Now, it loads a CD OK. The motor voltage output (which is built onto the SMPS... -
Hi all, I just need to know that, can i use SMPS type power supply to test and short circuit detection on a laptop motherboard?
I saw 95% of repair guys are using only Linear bench power supply. linear bench power supply is pricy, thats why i planned to get one SMPS supply.
i know that in linear power supply the noise will be very low comparing to SMPS supply.... -
I have this Huntkey HK340-72FP PC SMPS where I am facing a strange problem where the SMPS shuts down when the load on any of its 12v output rails goes above 2 amps while the rating of each 12v rail is above 10amps capable.
I have checked the following:
1. All output caps are OK, and all output rails read correct voltages at no load
2. All output diodes are OK
3. NTC is ok
4. Hi voltage cap on input correctly reads 150uF on LCR meter per the spec, also the bridge rectifier is OK
5. No short in main switching MOSFET
6. All other components... -
Hello,
I'm troubleshooting a PA speaker Mackie Th15 (schematics attached).
It is basically a smps with amp and some dsp.
The issue is that on the secondary side I read +/- ~23V instead of the expected +/- 38V. Indeed all secondary side and feedback/aux rails are like 1/2-3/5 of the expected values.
Q2, Q3, C35, C40, C33, C36, C41 and C42 were tested out of circuit with a component tester and read fine. Most of the other components on the primary were tested in circuit and seem to be fine. +HV to -HV on primary is ~330V.
By the way, the ferrite core of L10 is broken,... -
Hi everyone,
There actually was a time when early SMPS and late bakelite housed electrolytic caps coexisted in high end industrial gear. A friend of mine just got himself a CNC milling machine form that time with its first set of now 41 year old caps still installed in the PSU... and it's malfunctioning.
Two of the caps have already leaked slightly onto the board. I have not desoldered or measured any so far but they should qualify for replacement.
Now I'm wondering what to put in there as a replacement. First idea was state of the art low-ESR Nippon KY,...
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