32" Goodmans TV

[dumpystig]

Re: 32" Goodmans TV

The processor is trying to turn the TV on! But... why?

That's what it's meant to do. Amongst all the other things it does VCTP controls PSU on/off. When STBY_ON_OFF is high (1V7) its in stby, then when VCTP sends it low (0.6V or less) it powers up the PSU into full run mode.

[dumpystig]

Re: 32" Goodmans TV

Thing is, you are inputting a level to the VCTP whereas it is an output from VCTP

[tom66]

Re: 32" Goodmans TV

STBY_ON_OFF should be:

STBY - 1V7
RUN - 0.6V (mine is always 54-56mV)

Yea so connecting it to 5V makes it go into standby mode. So when the LED is lit solid, it is in standby.

The processor is trying to turn the TV on! But... why?

[dumpystig]

Re: 32" Goodmans TV

STBY_ON_OFF should be:

STBY - 1V7
RUN - 0.6V (mine is always 54-56mV)

[tom66]

Re: 32" Goodmans TV

Hmm

Connected STBY_ON_OFF to 5V(main) through 220 ohm resistor. Light stopped blinking and went solid. Press power button on remote. Starts blinking again.

????

[tom66]

Re: 32" Goodmans TV

Can only be done with display running, service mode on remote MENU, 4, 7, 2, 5.

What resistor? If you mean R084 it's a 2W and it's mounted above the board to allow heat dissipation.
And I've no idea why the change with the diode/caps?

It's not supposed to be mounted like that; you can clearly see the marking on the board intended for a smaller resistor, but they didn't have one, so they used a bigger one... a bit bodgy.

Of all things, the PSU is actually pretty well laid out. The main board is just dodgy.

HAHA the bugger came on 1st time....

Across C819:

STBY - 327VDC
RUN - 390VDC

Yeah so mine is stuck at 328V when in standby and when it is on.

Looks like I need to get it to turn on to reset it... i'll try jumpering pin #6.

[dumpystig]

Re: 32" Goodmans TV

HAHA the bugger came on 1st time....

Across C819:

STBY - 327VDC
RUN - 390VDC

[dumpystig]

Re: 32" Goodmans TV

Where are you measuring? I'll power it up now.

[dumpystig]

Re: 32" Goodmans TV

How do I get it to do a factory reset, though? That's the question...

Can only be done with display running, service mode on remote MENU, 4, 7, 2, 5.

What resistor? If you mean R084 it's a 2W and it's mounted above the board to allow heat dissipation.
And I've no idea why the change with the diode/caps?

[tom66]

Re: 32" Goodmans TV

Does your M/b have the extra HDMI x2 daughterboard?
I'm still prefering the sort-it-myself approach, up to now anyways.....

I don't think my inverters are faulty either, I can get the TV running fine most times, but this intermittent fault is really pissing me off. It's the start init procedure that is screwing up - I'm getting dropouts on the inverter start V from the M/b [PL803/1] so sometimes the b/l comes on then turn straight off and it goes into the marvellous LED-doing-different-flash-sequences-as-it-pleases-just-to-perplex-me-even-more sequence...

Mine only has one HDMI port. I read about the daughter board but mine doesn't have it.

Like yourself I'm struggling understanding these boards. Ive been having different displays re: that marvellous little blue LED, sometimes a 1Hz flash for about 2m before solid, other times 5-6 1Hz flash before solid... but at least I am able to get the set running most of the time.

It is very bizarre. The TV is very poorly designed. Why is there a resistor soldered on top of the board between two holes? The footprint was the wrong size, but they didn't want to update the design... Also, why is there a diode inbetween two capacitor shaped footprints? There's another diode occupying a cap footprint... It's just crazy bad design.

I can't get mine to power up at all any more. It's just dead to the world....

Yeah, I was thinking about the EEPROM, I think I read somewhere amongst all the data I have on these boards that it is re-written (from VCTP?) when initialising a factory reset... not 100% certain tho'.

How do I get it to do a factory reset, though? That's the question...



A question for you, what does your PFC bus read at when the set is on? Should be ~400V. Mine's at 328V. I'm wondering if it could be the problem...

[dumpystig]

Re: 32" Goodmans TV

Yeah, I was thinking about the EEPROM, I think I read somewhere amongst all the data I have on these boards that it is re-written (from VCTP?) when initialising a factory reset... not 100% certain tho'.

[dumpystig]

Re: 32" Goodmans TV

Like yourself I'm struggling understanding these boards. Ive been having different displays re: that marvellous little blue LED, sometimes a 1Hz flash for about 2m before solid, other times 5-6 1Hz flash before solid... but at least I am able to get the set running most of the time.

[dumpystig]

Re: 32" Goodmans TV

Does your M/b have the extra HDMI x2 daughterboard?
I'm still prefering the sort-it-myself approach, up to now anyways.....

I don't think my inverters are faulty either, I can get the TV running fine most times, but this intermittent fault is really pissing me off. It's the start init procedure that is screwing up - I'm getting dropouts on the inverter start V from the M/b [PL803/1] so sometimes the b/l comes on then turn straight off and it goes into the marvellous LED-doing-different-flash-sequences-as-it-pleases-just-to-perplex-me-even-more sequence...

[tom66]

Re: 32" Goodmans TV

There's plenty about these bloody boards thats odd...

Gona do some more testing, back soon

Thanks for your help.

The 24V line looks rather odd indeed... see scope trace

Bouncing from 8.5V to 11V at... guess what frequency.

[If you guessed 3 Hz, you'd be right.]

Everything in this PSU is sync'd to this 3 Hz signal! Where is it coming from? The only thing I can think of is the STBY_ON_OFF line... and the only place that comes from is the VCTP.

To test the display I plugged it into my Xbox 360 (got it off someone for cheap because of a broken disc tray, was easy to repair.) It was working perfectly, albeit making that rather annoying buzzing sound. Then I turned it off. I turned it on again, and briefly (half a second) there was an image (from Xbox) but then it switched off, and the LED started blinking... and it's been doing that even since.

I'm thinking software issues because I did turn it off by the plug. If it was writing to that eeprom at the time then who knows? It could be corrupted. I was using component video inputs, but I don't think that would matter.

[dumpystig]

Re: 32" Goodmans TV

There's plenty about these bloody boards thats odd...

Gona do some more testing, back soon

[tom66]

Re: 32" Goodmans TV

Hmmm...

It's tempting to buy a new main board.

I can get one for £20.

I will first try to find the actual fault with this board.

I don't think the inverter is faulty; see previous post. Disconnecting it shows similar problems.

Although, the 24V line to the inverter, while LED is flashing, is at 9.5V - 10.5V, changing slowly between values... very odd...

[tom66]

Re: 32" Goodmans TV

EEPROM removed, same problem.

WP is always high. WP should be low for normal operation according to svc manual, but write protect is actually active low. So it is good that it is high. Service manual is wrong.

Something else is wrong then...

[dumpystig]

Re: 32" Goodmans TV

Yep, I'm having similar probs which I'm attributing to the VCTP or its surrounding components - in particular the PDP_GO/BL_ON_OFF trigger for the inverter power up supply

[tom66]

Re: 32" Goodmans TV

STBY_ON_OFF is pulsing high-low every 3 Hz with a 75% duty cycle, now that tells me the set is trying to turn itself on, but why? It normally stays in standby when you plug it in and only turns on when you press the button on the remote...!

This seems to be a software issue - the VCTP is telling the PSU to turn on! Perhaps it is too early for it to turn on and it isn't ready... perhaps the PSU is also bad. I did pull the power out while it was on, and this could have killed it.

I will remove the EEPROM from its socket and see if the set boots up.

[tom66]

Re: 32" Goodmans TV

I lifted the main board out - no shorts or screws. I thought a screw may have fallen behind it. No such luck...

I think the VCTP is causing the problem. The PDP_GO/BL_ON_OFF is pulsing high, then low, at about 3 Hz, in time with the LED, and the 3.3VSTBY dipping by 600mV. Disconnecting the inverter cable doesn't help. There's no signal from the inverter telling the TV to shut off, and when disconnected the set does the same thing, so I think I can rule out the inverter.

The set is turning on, then turning off, for some reason.

Oddly, pressing MENU, CH_UP or VOL_DN makes the flashing stop. (Other buttons have no effect.) The set doesn't work, but it makes me suspect more and more that the VCTP is at fault.

1.8VSTBY is good too, solid 1.886V, no dips. That's 4.8% above nominal, but it should be fine as there is a typical ±5% tolerance on most cheap regulators.

PROTECT_DETECT, the signal going into the VCTP, is always low. Measured at R454.