Spectroniq PLTV-3250 wont start

[Test540va]

Re: Spectroniq PLTV-3250 wont start

The large device mounted on the heatsink it's about 2 transistor widths.

It's 4 diodes in a bridge rectifier arrangement in one package. Measure each of the diodes in the package just google bridge rectifiers to see the layout on the 4 pins.

Is this the Bridge Rectifier ? ? ? ? I have it circled in red.

[Krankshaft]

Re: Spectroniq PLTV-3250 wont start

The large device mounted on the heatsink it's about 2 transistor widths.

It's 4 diodes in a bridge rectifier arrangement in one package. Measure each of the diodes in the package just google bridge rectifiers to see the layout on the 4 pins.

[Test540va]

Re: Spectroniq PLTV-3250 wont start

You probably blew the line rectifier measure the diodes in the package.

Suprised that the fuse didn't blow.

Line Rectifier measure ? ??? where is that ? ?

[Krankshaft]

Re: Spectroniq PLTV-3250 wont start

You probably blew the line rectifier (or a few diodes in it) measure the diodes in the package with the diode checker function of the DMM.

Suprised that the fuse didn't blow.

[Test540va]

Re: Spectroniq PLTV-3250 wont start

Hello all... I'm afraid My inexperience has caused a major back-pedal I foolishly flipped the board upside down with the power supply ON and ZAP (blue light flashed and heard a small static-pop) DAMN ! ! I rechecked the LARGE cap for voltage and sure enough it was at 80... 79... 78.... etc... think if I replace that large capacitor it will be good to go again ?

[PlainBill]

Re: Spectroniq PLTV-3250 wont start

Sorry spent all day at work... unfortunately I won't be able to continue working on this project till Monday afternoon will be busy with previous engagements. but i do have one question for ya.... when I am measuring the voltage on the back of the PSU I assume it should be unplugged, correct ?

No. Do this with power on. Work carefully. Speaking from other's experience, 160VDC bites.

PlainBill

[Toasty]

Re: Spectroniq PLTV-3250 wont start

Please check device CRS2. The device mounted on the heatsink in the upper right of the top down picture of the entire board you posted. I've posted a zoomed pic of that device.

The front surface appears to be damaged. But, it might just be the lighting. Please verify whether it is surface glue/epoxy or is it a crack/hole in the casing?

You questioned the location of Q7 & ZD4. The other pic shows you their location.

Toast

[Test540va]

Re: Spectroniq PLTV-3250 wont start

Sorry spent all day at work... unfortunately I won't be able to continue working on this project till Monday afternoon will be busy with previous engagements. but i do have one question for ya.... when I am measuring the voltage on the back of the PSU I assume it should be unplugged, correct ?

[PlainBill]

Re: Spectroniq PLTV-3250 wont start

OK I hooked up the DMM just like you said and it read 157v....... I think it is a 160v PSU so that is good, right ? I also supplied a pic of the back of the board with no Flash. hope you can read it. T H A N K You very much for any support.

Excellent picture. On a 21" monitor it is easy to see everything.

Nominal voltage across the cap should be about 165 volts; 157 volts is within tolerances. That tells me the AC input, RF filters, and bridge rectifier are all fine.

I have identified 6 points on the output side of the board and crudely marked them A - F on the picture. Check the voltages on those. Set the meter to the 200 VDC range to start; reduce it to the 20 VDC range for any pins that measure less than 20 VDC. The black probe will go to the area I have outlined in black. The red probe will go to the other areas I have outlined, report the voltages you read at each.

Bill

[Test540va]

Re: Spectroniq PLTV-3250 wont start

Its now 11:07 pm here, got to give up for the night. Please check back, i will continue to work on this thing and post here daily

[Test540va]

Re: Spectroniq PLTV-3250 wont start

OK I hooked up the DMM just like you said and it read 157v....... I think it is a 160v PSU so that is good, right ? I also supplied a pic of the back of the board with no Flash. hope you can read it. T H A N K You very much for any support.

[PlainBill]

Re: Spectroniq PLTV-3250 wont start

OK first I have found another Forum here : http://www.circuitwork.com/archive/T.../msg00295.html

This guys says :

I've repaired about six of these, so far. You will need to replace all
> capacitors (in the power supply) that are bulging, or measuring high ESR.
> If you don't have a ESR meter, I can give you a list of 6-8 capacitors to
> replace blindly. You will also need to change a surface mount NPN
> Transistor (Q7, I think), I use a FMMT2222A and you will need to change a
> surface mount 15v zener diode (D4 or D7), next to Q7.
> That will fix it about half of the time.
>
> Sometimes you will also have to change IC1 (a 16 pin surface mount IC).
> Sometimes you will also have to change Q1 and Q2, both are 2SK3667 (I
> think), they will measure short if they are bad.
> And once I had to replace another surface mount IC (8 pin) in the primary
> section.


from what he says I want to replace the 15v Zener Diode ? can someone tell me if the CIRCLED component in the Picture is correct ?

I also found Q7 but it is soooo tiny, I also circled it in a different picture, can someone tell me if this is Right ?

I went to Radio Shack for the 15v Zener Diode, all they had were 12.5v Zeners so I found these on EBAY. Are these the proper replacements ?

http://cgi.ebay.com/15V-1-2-watt-Zen...d=p3286.c0.m14

First rule of thumb: Don't go blindly changing components because someone says this worked for him. Further, when he sprinkles lots of 'I think' s in the suggestions, be very, very cautious. Note that he referred to the zener as a surface mount package, the one you circled is a through-hole type.

I feel like a challenge tonight, so let's work this one out together. The first step will be to take a picture of the bottom of the pc board. Turn off the flash, have plenty of room light, and use a tripod or steady the camera so it isn't shaking. I will try to identify the points to measure.

The other thing to do is to hook the board up and measure the voltage across the large cap. Use the DMM you pictured, set to the 1000 VDC scale. I've indicated where the red and black probes should go (red probe to cap lead in red circle, black probe - well, you get the idea. Report the voltage you measure.

PlainBill

[Test540va]

Re: Spectroniq PLTV-3250 wont start

OK first I have found another Forum here : http://www.circuitwork.com/archive/T.../msg00295.html

This guys says :

I've repaired about six of these, so far. You will need to replace all
> capacitors (in the power supply) that are bulging, or measuring high ESR.
> If you don't have a ESR meter, I can give you a list of 6-8 capacitors to
> replace blindly. You will also need to change a surface mount NPN
> Transistor (Q7, I think), I use a FMMT2222A and you will need to change a
> surface mount 15v zener diode (D4 or D7), next to Q7.
> That will fix it about half of the time.
>
> Sometimes you will also have to change IC1 (a 16 pin surface mount IC).
> Sometimes you will also have to change Q1 and Q2, both are 2SK3667 (I
> think), they will measure short if they are bad.
> And once I had to replace another surface mount IC (8 pin) in the primary
> section.


from what he says I want to replace the 15v Zener Diode ? can someone tell me if the CIRCLED component in the Picture is correct ?

I also found Q7 but it is soooo tiny, I also circled it in a different picture, can someone tell me if this is Right ?

I went to Radio Shack for the 15v Zener Diode, all they had were 12.5v Zeners so I found these on EBAY. Are these the proper replacements ?

http://cgi.ebay.com/15V-1-2-watt-Zen...d=p3286.c0.m14

[ratdude747]

Re: Spectroniq PLTV-3250 wont start

no it does not.

[Wizard]

Re: Spectroniq PLTV-3250 wont start

1. Use capacitors we recommand here.
2. Q7 if you can't find it on component side or nor on solder side (SMD), the chances is that PSU is different.

3. Multimeter will only measure capacitance not ESR which is seperate meter made for measuring ESR. If caps says capxon, prudent to replace all. Carefully measure voltage on the secondary side (DC outputs with your multimeter on DC setting.) Unplug the PSU and remove from TV, check the big cap for stored voltage with meter first to prevent surprises and use 100K resistor to slowly discharge the cap. Next multimeter on diode mode, check the secondary diodes for shorts or opens.

Cheers, Wizard

[Test540va]

Re: Spectroniq PLTV-3250 wont start

I forgot to ask: Does anybody know if the "MULTIMETER" in the picture above has the ability to check the Transistors and Capacitors on this PSU ? Thanks Again.

[Test540va]

Re: Spectroniq PLTV-3250 wont start

Hello again, I soldered on 3 caps. I took a picture of the Board and Highlighted the Caps that got replaced. But nothing happened when I hooked it back up to the Monitor I guess i should go ahead and replace ALL capacitors on the board. Earlier in this Thread someone said they replaced Transistor (Q7) where is Q7 ? ? I can't find it, could someone help me find (Q7) ? ?

[Krankshaft]

Re: Spectroniq PLTV-3250 wont start

NO soldering gun!!

Unless you want to lift PCB traces and melt plastic.

A soldering iron 20 watts or so is what you need big difference .

[Test540va]

Re: Spectroniq PLTV-3250 wont start

Thanks for the reply, I will be sure to respond before the end of August on how this Process went, I am low on funds and can't afford the solder-gun n' stuff right now.... TO BE CONTINUED.

[sprocket]

Re: Spectroniq PLTV-3250 wont start

I'm fighting one of these also.

Had one given to me a year ago that was just out of warranty with sears that they wouldn't work on

I bought the PS then for $175.00 and it worked almost 1 year to the day and kicked off like I had pulled the plug

I see where I can get a PS now for around $59 bux but it really pains my arzz to do this every year for a 10 cent part

glen65
If you would please, I got confused on the above posts but, did you get yours to bench power on by injecting the 3.3 at [of] and did you get it to work for you in the set? A 3.3 battery should do that and without a schematic, I don't mind a little smoke or heat since I now have 2 units to fry.

test540va
CNS4 takes the cable from the board just left of the PS, CNS3 gets the cable from behind the chassis somewhere ... didn't trace it down

Thanks everyone ... interesting