Author Topic: Roberts R9954 AM-FM radio.  (Read 47 times)

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Turnip

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Roberts R9954 AM-FM radio.
« on: October 09, 2019,12:47:10 »
Hi folks,

Got one in as customer had dropped it into a bucket of water - 'Normal for Norfolk' some say.

When dry it 'motor-boated' due perhaps to a duff audio chip. Legend on the 8 pin chip was CHMC S.80 D820. Naturally couldn't get a schematic as doubtless made in China. Checked about a bit where a chap with a Steepletone radio suggested it might be a TBA820M.

As the only suggestion, got some - Total silence. Thought check about as pinning was identical. Noticed pin 7 had no 56 Ohm to +ve as the TBA820M

does. Success a bit, but noticed instability, so sorted around with a 22nf ceramic where from pin one to -ve - Normal working

Used to like Roberts radios, but not much - Chris.

Mulja tv repair portal

Roberts R9954 AM-FM radio.
« on: October 09, 2019,12:47:10 »

 

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