Panasonic TC-2253A (maybe not vintage) - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

TrevorM6TSE · 5th Mar 2008, 8:29 pm

Hi again All,

Thanks for the update Welsh Anorak. You've certainly answered it for me then!
As the tube sounds to be duff and I'm pretty sure my partner will not let it anywhere near the house it will be a case of getting rid

So, does anyone want it? Free to a good home and can be collected from Sheffield (where my Mum is) or Just off J28 (where I am)

PM me back if anyone is interested.

Mikey405 · 14th Mar 2008, 8:27 pm

There is a common fault on these sets which causes low brightness, and that is caused by a Zener diode in one of the LT supplies to the decoder going open circuit. (I think there were actually 2 in series). The supply to the decoder then goes up (by only a small amount) and causes the problem. I haven't serviced one of these sets for many years so I can't exactly remember the component numbers, but the zener itself is on the bottom panel. I don't think I've ever seen one of these with a really bad tube, although I'm sure there must have been dodgy ones about.

Hope this helps TrickyTrev.

From Mike.

BGmidsUK · 17th Mar 2008, 2:53 am

Quote:

Originally Posted by repairman 1234

HELLO,
If it has one try looking at the TDA3562A

Wasn't that also used in the dreaded F****ity ZX3000 chassis

great fun those sets, nothing was stable

From your post describing the symptoms my first thoughts were low-emission tube, I agree with Steve_P no harm in boosting the heaters a bit

BG

5th Mar 2008, 8:29 pm	#21
TrevorM6TSE Heptode Join Date: May 2003 Location: Old Tupton, Derbyshire, UK. Posts: 539	Re: Panasonic TC-2253A (maybe not vintage) Hi again All, Thanks for the update Welsh Anorak. You've certainly answered it for me then! As the tube sounds to be duff and I'm pretty sure my partner will not let it anywhere near the house it will be a case of getting rid So, does anyone want it? Free to a good home and can be collected from Sheffield (where my Mum is) or Just off J28 (where I am) PM me back if anyone is interested. __________________ I'd just like to say "Good luck, we're all counting on you"

14th Mar 2008, 8:27 pm	#22
Mikey405 Octode Join Date: Jul 2006 Location: Solihull, West Midlands and Beaford, Devon Posts: 1,626	Re: Panasonic TC-2253A (maybe not vintage) There is a common fault on these sets which causes low brightness, and that is caused by a Zener diode in one of the LT supplies to the decoder going open circuit. (I think there were actually 2 in series). The supply to the decoder then goes up (by only a small amount) and causes the problem. I haven't serviced one of these sets for many years so I can't exactly remember the component numbers, but the zener itself is on the bottom panel. I don't think I've ever seen one of these with a really bad tube, although I'm sure there must have been dodgy ones about. Hope this helps TrickyTrev. From Mike. __________________ G7TRF Last edited by Mikey405; 14th Mar 2008 at 8:33 pm.