24-11-2018, 11:42 AM
I have requested the service info for the Ultra Cub portable in the wanted section of this forum. The audio is ok but there in no raster on the set.
John
John
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Ultra Cub
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26-11-2018, 08:15 PM
If you weren't already aware the Ultra Cub model 6641 is fitted with the Thorn 980 chassis. For no raster check to see if the PL81A is showing signs of overheating, if so you probably have a resistor O/C or gone high value in the line osc stage. Great little sets.
John.
27-11-2018, 11:01 AM
(26-11-2018, 08:15 PM)Jayceebee Wrote: If you weren't already aware the Ultra Cub model 6641 is fitted with the Thorn 980 chassis. For no raster check to see if the PL81A is showing signs of overheating, if so you probably have a resistor O/C or gone high value in the line osc stage. Great little sets. The timebase circuits of the 980 series chassis. Geordie McBoyne.
29-11-2018, 12:50 PM
To Jayceebee. Thank you for the advice John. Yes, the PL81A is overheating so I shall check the resistors in the line osc stage as you suggest.
To Geordie McBoyne. Thank you for the scan of the 980 chassis timebase circuits. John
29-11-2018, 02:36 PM
No disrespect to David but I think you will find that the Trader scan that Mike (Crackle) posted in response to your request a lot easier to see.
29-11-2018, 03:36 PM
Yes, In fact I have been looking at that one Terry and it also shows the complete cicuit.
John |
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