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Need some advice - Stromberg Carlson Record Player
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Return to top of page · Post #: 16 · Written at 6:29:33 PM on 10 January 2015.
	MonochromeTV Location: Melbourne, VIC Member since 20 September 2011 Member #: 1009 Postcount: 1182
I believe your unit may be called the Stromberg Carlson "Maestro Gram". Along with the floor standing "Melody Maker", they both use a 54A12 chassis.

Return to top of page · Post #: 17 · Written at 12:59:31 AM on 11 January 2015.
	Marcc Location: Wangaratta, VIC Member since 21 February 2009 Member #: 438 Postcount: 5254
The new one will be the value I pointed out 630VDC (or more) I repair so have stocks. Bit hard & pricy to order 1. Evatco & Saville have them, plus others If you check resistors do not use half watt from the supermarket, some of those will not handle the volts, use 1 Watt. If you do not need to order in new electrolytics put two 0.0047mfd (472) in series, or two 0.001mfd (102) in parallel. That cap is likely on a plate & that is the most likely one, other than unused electrolytics, to fail. Marc

Return to top of page · Post #: 18 · Written at 2:37:52 AM on 11 January 2015.
	GTC Location: Sydney, NSW Member since 28 January 2011 Member #: 823 Postcount: 6687
put two 0.0047mfd (472) in series I was taught that balancing resistors should be used when connecting electros in series (to equalise the voltage across each).

Return to top of page · Post #: 19 · Written at 1:08:56 PM on 11 January 2015.
	MonochromeTV Location: Melbourne, VIC Member since 20 September 2011 Member #: 1009 Postcount: 1182
I've just found that there are two versions of the 54A12 chassis. Both are identical apart from the earlier version using a 6X5GT rectifier. The 6X5GT version is in the AORSM, Vol. 13 & the 6X4 version is in the JR Valve Manual..

Return to top of page · Post #: 20 · Written at 9:54:06 PM on 11 January 2015.
	Marcc Location: Wangaratta, VIC Member since 21 February 2009 Member #: 438 Postcount: 5254
The balancing resistors normally apply to the electrolytics where two, normally less than the applied voltage are used. Electrolytics can be cranky. The Heatkit CRO here has two 450V Ecaps on EHT with 470K resistors across them runs around 730V an Honor Capacitance - Resistance Analyser I scored had two 350V in series & one of them let go. They also forgot to solder them together when they made the cap in the factory. There is no way that you would get away with under 25 Meg resistors with these two and there is no way that the applied voltage will punch two 630V NP ones through. That balancing act would result in a leaking cap effect. Screen decouplers with a resistance of 50 meg, or less are a fail & coupling 200Meg or less are a fail & if I test them for leakage, its with an insulation tester. Sprung a Mica in a Tasma 1103 that way last week. Marc

Return to top of page · Post #: 21 · Written at 6:54:54 PM on 11 March 2015.
	MonochromeTV Location: Melbourne, VIC Member since 20 September 2011 Member #: 1009 Postcount: 1182
Here is some more info on the Stromberg Carlson 54A12, or Maestro Gram. Stromberg Carlson Maestro Circuit Diagram (6X5) Stromberg Carlson Maestro Circuit Diagram (6X4)

Return to top of page · Post #: 22 · Written at 11:50:31 PM on 11 March 2015.
	GTC Location: Sydney, NSW Member since 28 January 2011 Member #: 823 Postcount: 6687
Nice poster. Where did you find that?

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