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 Commodore Identification
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 Return to top of page · Post #: 31 · Written at 11:42:11 AM on 7 September 2017.
BringBackTheValve's Gravatar
 Location: Linton, VIC
 Member since 30 December 2016
 Member #: 2028
 Postcount: 240

Spot on Ian! Thank you.

It's a Tasma. Best best estimate is a cross between a 295 and 365.

Sticking points---a) no voltage divider, and b) 6B7 valve instead of a 75.

All in all, a great effort,

Thank you everyone, what a terrific forum.


 
 Return to top of page · Post #: 32 · Written at 9:02:47 PM on 7 September 2017.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 3967

75 became a 6SQ7. That should ring alarm bells. Tasma tended to use a lot of Philips valves. Further the circuit would have to be different as #75 is a Triode double diode & 6B7 is a Pentode double diode.


 
 Return to top of page · Post #: 33 · Written at 10:40:39 AM on 8 September 2017.
BringBackTheValve's Gravatar
 Location: Linton, VIC
 Member since 30 December 2016
 Member #: 2028
 Postcount: 240

Yes, and coupled with the missing voltage divider present in similar chassis types, it is now very clear I have to sit down and trace out the exact schematic.

I have a bad feeling your earlier post may be prophetic, ie, ---this may be a bit of this and a bit of that---.

I also note the electros in the chassis are top mounted. My chassis has those holes punched, the electros however are underneath.

Curiouser and curiouser---


 
 Return to top of page · Post #: 34 · Written at 12:49:31 PM on 8 September 2017.
Fred Lever's Gravatar
 Location: Toongabbie, NSW
 Member since 19 November 2015
 Member #: 1828
 Postcount: 671

Hi the electros will be replacements, you can see the witness marks on the metal around the original holes where the insulating washers were under the can nuts.
Fred.


 
 Return to top of page · Post #: 35 · Written at 2:03:00 PM on 8 September 2017.
BringBackTheValve's Gravatar
 Location: Linton, VIC
 Member since 30 December 2016
 Member #: 2028
 Postcount: 240

Yes, but the electros themselves are vintage (and weeping) and I still need to figure out why the voltage divider is missing---if it ever existed in the first place, plus the 75/6B7 problem.

No easy way out of this, I must trace out the wiring.


 
 Return to top of page · Post #: 36 · Written at 5:18:16 PM on 8 September 2017.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 3967

We must be careful not to assume it's actually a TASMA and not all sets had a voltage divider on the AGC. There are also similarities with a Stromberg Carlson 59 and there were a lot of sets with that valve compliment and it is unwise to think at this point that what it has, is what it should have.

I would agree that the Electrolytic caps are not original, That vintage they were likely chassis mounted wets. The plot will be similar to many and in the case of sets like that, I reverse engineer them by initially setting up a layout diagram, using the AutoCAD & then play join the dots.

Colour is you friend: Blue for screens, Orange cathode (filament) to field, Red for the rest of the main B+,Green heaters etc. Then its translated & put into a circuit using the AutoCAD. Once there is a circuit, you can see where its all gone pear shaped.

I my case it may be a lot of effort, but when customer satisfaction is the primary concern & they want it working if it is achievable:So be it.

Marc


 
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