UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Philips T-Vette

dazzlevision · 28th Apr 2007, 7:44 am

Hello Trevor,

I have replied to the points you raised - in CAPITALS, below.

Tonight I started to dismantle the set and wonder if you have any suggestions as to how best one can improve access without disconnecting much of the wiring! It really is a bit of a bird's-nest!! IF I RECALL CORRECTLY, THE LEADS LENGTHS ARE SUFFICIENT TO WORK ON THE MAIN PCB WITHOUT DISCONNECTING ANY WIRING. THERE ARE TWP SCREWS THAT SECURE THE MAIN PCB - AT THE REAR. I THINK I FOUND IT BEST TO HAVE THE SET ON ITS SIDE, IN ORDER TO WORK ON THE MAIN PCB, WHICH SHOULD TILT OUT ENOUGH TO ACCESS MOST COMPONENTS. I'M PRETTY SURE I RAN MINE IN THIS POSITION - WITH SOME INSULATION AROUND THE DY51's ANODE!

I wonder if it would be better to remove the CRT and gain access through that space rather than a massive unsoldering exercise? (I think photographs will also be needed!) I DON'T THINK THIS IS NECESSARY.

The sound symptom on 405 is complete silence but on 625 there is plenty of useful hiss...but no actual sound. I am therefore wondering whether the o/p trannys may have survived - YOU ARE PROBABLY CORRECT, BUT I WOULD CHECK THOSE 1 OHM RESISTORS. ON 625, THE 6MHz FM "INTERCARRIER" SOUND IS TAKEN FROM A SEPARATE DIODE DETECTOR IN THE VIDEO DETECTOR STAGE. ON 405, IT IS TAKEN OFF THE VISION IF STRIP EARLIER ON.

By the way you mentioned one o/p transistor as an OC81 but mine has an AC128 and an AC127...so is the OC81 an equivalent for the AC128? YES, BUT WITH A SLIGHTLY DIFFERENT METAL CASE.

Last point...the manual makes much of the need to use a heat sink when re-fitting transistors...but for the life of me I can't see there is any room to use anything other than a very small pair grips on the lead being soldered...what's you experience of this issue? AS LONG AS YOU ARE QUICK WHEN SOLDERING, THERE SHOULDN'T BE A PROBLEM. I HAVE NEVER DAMAGED A GERMANIUM TRANSISTOR THROUGH SOLDERING.

FROM WHAT YOU SAID ABOVE, YOU SEEM TO HAVE THE CORRECT PHILIPS SERVICE MANUAL....? DOESN'T THIS COVER ACCESS FOR SERVICE? MY MANUAL IS IN THE LOFT SOMEWHERE, SO I CAN'T EASILY REFER TO IT! I DO RECALL THE NEED TO DRESS CERTAIN WIRES CORRECTLY WHEN RE-ASSEMBLING, IN ORDER TO AVOID INFERIOR PERFORMANCE.....

I WOULD CERTAINLY REPLACE THE THREE AF11x TRANSISTORS IN THE SOUND STAGES, BEFORE DELVING IN FURTHER.

GOOD LUCK,

DAZZLEVISION

28th Apr 2007, 7:44 am	#25
dazzlevision Dekatron Join Date: Sep 2003 Location: Near Swindon, North Wiltshire, UK. Posts: 3,612	Re: Philips T-Vette Hello Trevor, I have replied to the points you raised - in CAPITALS, below. Tonight I started to dismantle the set and wonder if you have any suggestions as to how best one can improve access without disconnecting much of the wiring! It really is a bit of a bird's-nest!! IF I RECALL CORRECTLY, THE LEADS LENGTHS ARE SUFFICIENT TO WORK ON THE MAIN PCB WITHOUT DISCONNECTING ANY WIRING. THERE ARE TWP SCREWS THAT SECURE THE MAIN PCB - AT THE REAR. I THINK I FOUND IT BEST TO HAVE THE SET ON ITS SIDE, IN ORDER TO WORK ON THE MAIN PCB, WHICH SHOULD TILT OUT ENOUGH TO ACCESS MOST COMPONENTS. I'M PRETTY SURE I RAN MINE IN THIS POSITION - WITH SOME INSULATION AROUND THE DY51's ANODE! I wonder if it would be better to remove the CRT and gain access through that space rather than a massive unsoldering exercise? (I think photographs will also be needed!) I DON'T THINK THIS IS NECESSARY. The sound symptom on 405 is complete silence but on 625 there is plenty of useful hiss...but no actual sound. I am therefore wondering whether the o/p trannys may have survived - YOU ARE PROBABLY CORRECT, BUT I WOULD CHECK THOSE 1 OHM RESISTORS. ON 625, THE 6MHz FM "INTERCARRIER" SOUND IS TAKEN FROM A SEPARATE DIODE DETECTOR IN THE VIDEO DETECTOR STAGE. ON 405, IT IS TAKEN OFF THE VISION IF STRIP EARLIER ON. By the way you mentioned one o/p transistor as an OC81 but mine has an AC128 and an AC127...so is the OC81 an equivalent for the AC128? YES, BUT WITH A SLIGHTLY DIFFERENT METAL CASE. Last point...the manual makes much of the need to use a heat sink when re-fitting transistors...but for the life of me I can't see there is any room to use anything other than a very small pair grips on the lead being soldered...what's you experience of this issue? AS LONG AS YOU ARE QUICK WHEN SOLDERING, THERE SHOULDN'T BE A PROBLEM. I HAVE NEVER DAMAGED A GERMANIUM TRANSISTOR THROUGH SOLDERING. FROM WHAT YOU SAID ABOVE, YOU SEEM TO HAVE THE CORRECT PHILIPS SERVICE MANUAL....? DOESN'T THIS COVER ACCESS FOR SERVICE? MY MANUAL IS IN THE LOFT SOMEWHERE, SO I CAN'T EASILY REFER TO IT! I DO RECALL THE NEED TO DRESS CERTAIN WIRES CORRECTLY WHEN RE-ASSEMBLING, IN ORDER TO AVOID INFERIOR PERFORMANCE..... I WOULD CERTAINLY REPLACE THE THREE AF11x TRANSISTORS IN THE SOUND STAGES, BEFORE DELVING IN FURTHER. GOOD LUCK, DAZZLEVISION