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ben · 26th Jan 2023, 2:49 pm

I am restoring a few Philips CP- series sets for a project. The common denominator, which also affects the CTX remote sets, is the leaky 2.4v 100mAh memory battery. These damn things have caused damage to the PCB, in one case writing off a set. The original yellow ones seem to leak less, but the white and blue replacements sold in the last couple of decades really were nasty.

A very similar scenario happens in some Thomson sets, which use a disc-shaped Varta type.

So far I have replaced them with what I had to hand, namely battery caddies from old transistor radios with 2x AAA 1,5v, mounted inside the cabinet off the main PCB. However, I'm looking at more elegant less time consuming options. I have a few lithium cells from wireless earphones (like this one, 45mah, 3,7 V). Voltage is a bit higher, but I don't expect it to matter too much. Has anyone tried using one?
The charge circuit is derived from the 6v line via a diode with a series resistor 3901 presumably to limit the current.

26th Jan 2023, 2:49 pm	#1
ben Dekatron Join Date: Aug 2006 Location: Madrid, Spain / Wirral, UK Posts: 7,498	Philips CP90 and others: memory battery. I am restoring a few Philips CP- series sets for a project. The common denominator, which also affects the CTX remote sets, is the leaky 2.4v 100mAh memory battery. These damn things have caused damage to the PCB, in one case writing off a set. The original yellow ones seem to leak less, but the white and blue replacements sold in the last couple of decades really were nasty. A very similar scenario happens in some Thomson sets, which use a disc-shaped Varta type. So far I have replaced them with what I had to hand, namely battery caddies from old transistor radios with 2x AAA 1,5v, mounted inside the cabinet off the main PCB. However, I'm looking at more elegant less time consuming options. I have a few lithium cells from wireless earphones (like this one, 45mah, 3,7 V). Voltage is a bit higher, but I don't expect it to matter too much. Has anyone tried using one? The charge circuit is derived from the 6v line via a diode with a series resistor 3901 presumably to limit the current. Attached Thumbnails __________________ Regards, Ben.