Panasonic TC-51M02 No sound No picture

dahbrown · Joined: 31 May 2007 Posts: 31

Hi,
I have the above TV which has a problem of no sound and no picture.
I ordered the schematic from Panasonic. The chassis is MX-5Z. It is the same cct as on the site here for TC-21S85RQ (MX-5 chassis).

I have purchased a couple of service manuals, but they have all been in Russian. Are there any English versions readily available?

The TV is a PAL BG 240v

On the diode (D831) near the transformer (T801), I have 120V, on the other side of the diode I only have 12v. So I replaced both the diode and the capacitor (C831). This made no difference.

I am suspecting that the HOT is open/short circuit which is component Q551 (I think). Or could it be the transformer T552.

What can I do to verify?

Thanks
Dave

minnie · Joined: 18 Aug 2005 Posts: 2880 Location: Hell

Ohm the HOT and see if it's shorted.

dahbrown · Joined: 31 May 2007 Posts: 31

Thanks for that tip. I have a short between Base & emitter, and an open cct between collector & base and collector and emitter.

Does this mean that the HOT is shot!? The HOT has the part number- D2539. If it is faulty is this a standard replacement part?
If it is stuffed, what would have caused it? The transformer?

Thanks for your help

minnie · Joined: 18 Aug 2005 Posts: 2880 Location: Hell

dahbrown · Joined: 31 May 2007 Posts: 31

Thanks for that. So I guess that I need a new one. Looking at the datasheet there should be 50 ohms between B & E?

dahbrown · Joined: 31 May 2007 Posts: 31

I have just rechecked the resistance between B & E, and there is around 45 ohms. My multimeter was playing up,. so I bought a new one.

Does this mean that the HOT is OK?
What else can I check?

Guest · Posted: Sun Jun 03, 2007 5:31 pm Post subject:

between B-E it should be short and vice versa,and +on the base and - on the colector should read OL,and the other way around should be betwen 0.500 and 0.800, use the diode measurement,and the easy way to check the hot is, with the power cord plugged in the power <<do not turn on the TV>> than with DC volts, check the collector for how many volts, if is 110 volts set you should have up 140 more or less i don't know your set also check the big cap use -neg as a good ground for the hot volts check,the big cap also should have some what around 140 or a litle less than the hot.

dahbrown · Joined: 31 May 2007 Posts: 31

Nope. Only getting around 70VDC on the HOT.
Checked the 5V & 8V regulators and they are only outputting 3.54VDC with 5VDC input to them. I think that this should be 11V input.
IC1202 (5V regulator) 11 VDC input - 4.9VDC output
IC851 (5V regulator) 5VDC i/p - 3.54VDC o/p
IC852 (8V regulator) 5VDC i/p - 3.54VDC o/p
IC802 Should have 140V on pin 1, but has 71VDC
IC451 (Vertical Deflection IC) only has 11.71 for pin 6 (VCC)
T552( HV transformer) Pin 9 & 10 only has 71V, should be 140V
I also resoldered the Vertical IC, made no difference.

What part number is the switched mode power supply. Is this T801?
What else can I check to see what the problem is?