Philips G11

[neil29]

I've been having a look at the set I got from Mike last week, and he said it had frame collapse.
Even though I've changed the TDA 2900, it still wont co-operate with me; also it keeps blowing two fuses on the line output panel (the 500 milliamp and the 800 ones).
Any suggestions most welcomed.

thanks,neil.

[Michael Maurice]

I wonder if the supply rectifier diode is s/c?

Also change 680uF caps that decouple the supply.

[coil1234]

Hello Neil,
Glad the G11 has found a good home, I was initially interested but only for spares.

Looking at my manual for the "700 Series" the supplies through the 500mA (FS151) & 800mA (FS143) fuses originate from the same winding on the LOPT and are rectified by D138.
FS143 feeds LT3 (37 Volts) to the TB panel and is smoothed by C144 on the Line Scan Panel.

FS151 feeds LT4 (37 Volts) to the IF panel where it is smoothed by C47, LT4 goes via Fusable resistor R46 on the IF panel, my diagram also shows this supply fed out from the IF panel on pin 1 of connector 5Z (some sets only!)

You may have multiple faults, however the obvious fault to cause both fuses to blow would be the rectifier diode D138 short circuit (as sugessted by Michael Maurice above).

Hope this helps in restoring another of these excellent sets, good luck

Mike A

[Sideband]

Originally Posted by neil29

but even though ive changed the TDA 2900 etc it still wont co-operate with me,

Hi Neil. I hope that is supposed to say TDA2600! I suggest you also try the chip holder. These were notorious for giving trouble and make sure you have fresh heatsink compound between the chip and the heatsink. I should also mention the importance of making sure the large 470UF smoothing cap on the power supply has been changed. These used to arc and cause all sorts of problems including a cracked CRT neck!


Rich.

[Dr-Watts]

The chip should be a TDA2600!
If the wrong chip is fitted, that could explain your problem!
Take the chip out and try again with new fuses fitted, if it's the chip, the fuse will stay intact --- Hopefully

These chips were pretty unreliable and blown fuses were regular when the chip went faulty.
The chip holder could also be suspect !

Also have a look at...

If the voltage at pin 16 of the TDA2600 is much less than 19V, check C2099 and C2100 both are 1000uf.

Also have a look at C2060, C4029 and R2066 as dry joints are very popular here, ( just like everywhere else on this chassis ! )
It's certainly worth sticking all these caps on a meter and checking their worth.

I'd also check the wiring harness, just in case it's rubbed through somewhere near the frame stage. (Another forgotten favourite !)

I loved the G11, when I started as a apprentice in Luton I did G11 after G11 !
God only knows why they were so popular in sunny Luton.

A TDA2600, a handful of 1N4007s, a couple of BY223s (the funny red ones )and a BU208A and you'd be able to get any poorly G11 in the field.
Oh, and a smoothing cap, of course. I've still got the circuit if you need a copy...

Hope this is of use to you.

Dave W

[neil29]

One thing I forgot to ask about was D138 on the line output panel.
I don't have any exact replacements, what would be the next best one to try?
cheers neil.

[Welsh Anorak]

Hi
I'd suggest a BY299 as it's happy with flyback pulses and will pass 2A happily.
Unfortunately it's not red....

Glyn

[neil29]

Well ive been tinkering with this set again . and the picture below is the result . there is no sound nor can the brightness be turned down. any ideas??. thanks neil. ps this is not the set that i fixed fairly recently..

[Red to black]

Hi,
Here is a list of stock faults.

Cheers,
Baz

[Hybrid tellies]

That list of stock faults is brilliant. But looking at your picture it looks like you have excessive green drive. I would start by checking voltages around the green output stage, I would expect the voltage on the green cathode of the crt is a bit on the low side. Hopefully this is due to an output or driver fault. As for the no sound fault check the voltages around that output stage which I think is an ic on this set.

[Welsh Anorak]

Hi
The sound fault is often the fusible resistor that feeds the output pair on the IF panel springing open for no reason.
Glyn

[neil29]

Well ive been at it again and swapped the if panel and decoder. and the sound has come back and i no longer have a green tint to the picture. but there is still no picture of any sort even after checking parts with the fault list above. also when i put the teletext on the set seems to take offence and the raster does what i can best describe as pulsate as if its about to collapse. well im stuck as usual..any ideas. thanks neil.

[Red to black]

Here are 2 more faults listed for you.
(I no longer have a diagram) would anyone care to post one?

1)dark pic & no colour Ht pulsating : IC2510
2) No video : D4090 S/C (zener 4V7)

Have you tried temporarily disconnecting the text board?

Cheers,
Baz

Ps. sorry these faults are already on the list I posted earlier

[gec2110]

i think that there is fuse gone on the Line timebase panel
the 200volt line is probably missing have a manual at home
and a pye studio fault guide
1 check the fuses and the condition of the line time base before looking else where
the 12volt regulator could also be faulty on the if panel
if it is text? is there a voltage which drives the RGB from the text panel which is missing
or has a fuse lost its life somewhere

[gec2110]

Thsese G11 were good and i liked them very much but why so many stock faults and some poor quality componets the smothing cap and the frame ic with that nasty low profile holder i thought that they had learned the lesson from the really bad awful G9
G11 not the best set of all time but it is pretty hard to beat
and i love them