Hello all, Can someone help with this set.. when switched on the EHT comes up but there's no picture of any description or sound and when I turn up the brightness there's nothing on the screen. and even the green LED on the tube base is not glowing. and the trouble is I cant find my service info for it so i'm a bit lost on this one.
Cheers
Neil.
Hi Neil
If my memory serves me correctly try the blue square resistor on the swing down panel, 10 ohms I think.
From Television mag Jan 1989.
Check D657 and the output transistors TR654/5/6 on the CRT base panel, one of the transistors fail and destroys the diode.
Frank
Well you were spot on with the resistor colourmaster ?. as it looked ok from the casual glance but when I looked underneath it has burnt out with the coating peeling off it. do you think I should check the diode and transistors on the tube base or should I just replace the resistor and hope for the best.
Cheers
Neil.
The article states the current through the diode should be 25-30ma, faulty transistors raise it to around 90ma, if the current is correct I would leave well alone.
Good info from Colour Master.
Never seen one of these sets, well after my time, just going off the write up.
Frank
Just fit a new resistor, it will be absolutely fine. Give the chopper transformer joints a look over, dry joints here can often cause int loss of CRT heaters.
John.
I forgot to ask what's the minimum wattage resistor I can get away with as there's no marking on it now.
Thanks
Neil.
What is the resistor designation Rxxx from the PCB print? I can look it up in the manual for you.
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Hi Chris, It's R613.
Cheers
Neil.
Here you go
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Thanks Chris ? .
Well replacing the resistor has restored the sound and picture ? but the field hold has very little effect at stopping it rolling and there is a blank strip in the middle of the picture too. and to top it off the set will not respond to the remote which I have confirmed works with an infrared tester. can anyone help with these little problems.
Thanks
Neil.
Try these. its always worth searching our blog database Just type in tx10 or whatever in the search or manually browse categories.
the field hold has very little effect at stopping it rolling
TX10 FIELD ROLL R813(121K)
a blank strip in the middle of the picture too
TX10 WIDE BLACK LINE ACROSS PIC,TDA2576A
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Hi Neil, is this a metal or plastic chassis TX10? The TDA2576A on the later version of the metal chassis can cause this, if my memory is correct the "Sandcastle" output becomes distorted. Note that in very early TX10s the sync and line generator used a TDA2576.
Loss of remote control is quite rare but check the earthing of the IR pre-amp module, remove the PCB and check the metal earthing part is clean and retention it to make good contact with the can. Is the remote you're using an original or copy?
A very rare cause of no remote operation can be caused by the off/on switch if standby contacts are permanently closed. An easy way to test for this is with the set powered on switch off and back on at the wall socket, if the switch is OK the set will be in standby when power is reapplied.
John.
Hi John. The remote thing was my mistake ? as I thought the aftermarket remote RCU1789 which has supersound/mono/stereo buttons etc would operate the set, I was wrong.. and when I tried the non stereo basic wedge remote it all works fine. and the set is a metal chassis one dating from 1982.
Cheers
Neil.
RCU1789 (equivalent to T789) is for the TX100 series with a totally different chipset so you would have problems there. ?
John.
Hi John, it's a TDA2576A.
So it's a later metal chassis with separate line and field oscillators, the plastic chassis used a TDA2578A which combined both with the field osc driving a TDA3652 output IC. Any chance of a picture of the symptoms?
John.
Hi John, I did take a photo of the problem but I cant load it onto my laptop for some reason?.
Its finally dawned on me that this set is ok and my Philips PM5508 has a fault. I only came to the conclusion ? when I plugged in my Bush T20A last night and it displayed the same fault which also caused me too think 2 other sets were faulty ?.and ive also had some shocks from the front panel too despite the fact the earths are all connected in the unit and in the mains socket etc. but never mind as I have another pattern generator that I can use in the meantime.
Cheers
Neil.
