BT Tele 300A buttset - UK Vintage Radio Repair and Restoration Discussion Forum

oldmoley1 · 9th Mar 2015, 8:53 pm

Just managed to acquire two, shall we say, challenged Tele 300As. Neither work properly by all accounts, so should be an interesting project. A couple of questions for all you knowledgeable people out there:

a. who manufactures this phone? It looks very much like a set made by Greenlee.
b. I imagine that I shall be delving deep into the world of circuit boards etc. - are there any known common defects with this model?

Hoping someone can help!

AC/HL · 9th Mar 2015, 11:33 pm

It would appear to be Chesilvale for the A version: http://www.greenlee.com/BT/tele300.html

Biggles · 10th Mar 2015, 5:43 pm

Don't know if they apply to your particular model but common faults we have had (and fixed) on ours are button problems, connection lead intermittent and a crystal oscillator failure which turned out to be a dry joint. This manifested itself as everything working apart from no dialling function from keypad. Internal battery dead can also give problems with the monitor function etc. Hope that gives you a starting point.
Alan.

oldmoley1 · 10th Mar 2015, 7:26 pm

Many thanks to both of you for your help. I'll post again with progress......

oldmoley1 · 12th Mar 2015, 6:27 pm

Had a look at both buttsets today, and have had a mixed result. The first now works well in most respects, except that it doesn't ring out when called, and no dial tone or speech can be heard through the loudspeaker when set to this mode. If the set is called from another phone, the ringing cadence can be heard faintly through the earpiece. The speaker itself seems to be OK, since plenty of noise can be heard when set to monitor.

The second remains completely dead. I've fitted a new battery, and have stripped the unit to see whether there are any obvious problems. All wiring seems OK, and I have established that current is passing from the battery into the board. How far it is actually getting remains a mystery though.......

The PCB does not appear to lend itself to repairs. Anyone got any further suggestions before this unit enters my boys' box of things that might come in useful sometime.....?

9th Mar 2015, 8:53 pm	#1
oldmoley1 Tetrode Join Date: Apr 2014 Location: Northampton, Northants, UK. Posts: 84	BT Tele 300A buttset Just managed to acquire two, shall we say, challenged Tele 300As. Neither work properly by all accounts, so should be an interesting project. A couple of questions for all you knowledgeable people out there: a. who manufactures this phone? It looks very much like a set made by Greenlee. b. I imagine that I shall be delving deep into the world of circuit boards etc. - are there any known common defects with this model? Hoping someone can help!

9th Mar 2015, 11:33 pm	#2
AC/HL Dekatron Join Date: Nov 2003 Location: Heckmondwike, West Yorkshire, UK. Posts: 9,642	Re: BT Tele 300A buttset It would appear to be Chesilvale for the A version: http://www.greenlee.com/BT/tele300.html

10th Mar 2015, 5:43 pm	#3
Biggles Rest in Peace Join Date: Feb 2004 Location: Hexham, Northumberland, UK. Posts: 2,234	Re: BT Tele 300A buttset Don't know if they apply to your particular model but common faults we have had (and fixed) on ours are button problems, connection lead intermittent and a crystal oscillator failure which turned out to be a dry joint. This manifested itself as everything working apart from no dialling function from keypad. Internal battery dead can also give problems with the monitor function etc. Hope that gives you a starting point. Alan.

10th Mar 2015, 7:26 pm	#4
oldmoley1 Tetrode Join Date: Apr 2014 Location: Northampton, Northants, UK. Posts: 84	Re: BT Tele 300A buttset Many thanks to both of you for your help. I'll post again with progress......

12th Mar 2015, 6:27 pm	#5
oldmoley1 Tetrode Join Date: Apr 2014 Location: Northampton, Northants, UK. Posts: 84	Re: BT Tele 300A buttset Had a look at both buttsets today, and have had a mixed result. The first now works well in most respects, except that it doesn't ring out when called, and no dial tone or speech can be heard through the loudspeaker when set to this mode. If the set is called from another phone, the ringing cadence can be heard faintly through the earpiece. The speaker itself seems to be OK, since plenty of noise can be heard when set to monitor. The second remains completely dead. I've fitted a new battery, and have stripped the unit to see whether there are any obvious problems. All wiring seems OK, and I have established that current is passing from the battery into the board. How far it is actually getting remains a mystery though....... The PCB does not appear to lend itself to repairs. Anyone got any further suggestions before this unit enters my boys' box of things that might come in useful sometime.....?