Both right channels dead on dual deck JVC KD-W110 cassette player

[JimBanville]

It's not the cables. Lol. The audio and LED meter for the right channel from both decks shows no signal. Can someone please tell me what to check first? I went ahead an reflowed the solder on most of the IC's. No change. Thanks!!!!

[petehall347]

Re: Both right channels dead on dual deck JVC KD-W110 cassette player

most likely the record switch needs cleaning

[JimBanville]

Re: Both right channels dead on dual deck JVC KD-W110 cassette player

most likely the record switch needs cleaning

It doesn't have a record/play switch.

[redwire]

Re: Both right channels dead on dual deck JVC KD-W110 cassette player

Is there a schematic/service manual for it? Can you cross-record, that is from R ch on one deck to the other? Just to see if there is internal R ch activity, compared to Line Out.
No R ch in both decks likely means the REC-PLAY switch circuitry or further downstream is the problem. If it's only one channel in one deck, easier to track down.
I would go to the tape head preamps IC801, IC802 and confirm there is signal output there.

Wild guess is after those tape-head pre-amp IC's is the electronic switching CD4066B's IC803, IC804 which I would suspect.
Write down DCV measured at their 14-pins. It's easy to see the R and L circuits, take comparison readings between channels, to see if a mux shorted in the IC.

[JimBanville]

Re: Both right channels dead on dual deck JVC KD-W110 cassette player

Is there a schematic/service manual for it? Can you cross-record, that is from R ch on one deck to the other? Just to see if there is internal R ch activity, compared to Line Out.
No R ch in both decks likely means the REC-PLAY switch circuitry or further downstream is the problem. If it's only one channel in one deck, easier to track down.
I would go to the tape head preamps IC801, IC802 and confirm there is signal output there.

Wild guess is after those tape-head pre-amp IC's is the electronic switching CD4066B's IC803, IC804 which I would suspect.
Write down DCV measured at their 14-pins. It's easy to see the R and L circuits, take comparison readings between channels, to see if a mux shorted in the IC.

Sorry but I don't have the schematic. Do I need to have a tape playing to test those IC's? Thanks!

[JimBanville]

Re: Both right channels dead on dual deck JVC KD-W110 cassette player

Is there a schematic/service manual for it? Can you cross-record, that is from R ch on one deck to the other? Just to see if there is internal R ch activity, compared to Line Out.
No R ch in both decks likely means the REC-PLAY switch circuitry or further downstream is the problem. If it's only one channel in one deck, easier to track down.
I would go to the tape head preamps IC801, IC802 and confirm there is signal output there.

Wild guess is after those tape-head pre-amp IC's is the electronic switching CD4066B's IC803, IC804 which I would suspect.
Write down DCV measured at their 14-pins. It's easy to see the R and L circuits, take comparison readings between channels, to see if a mux shorted in the IC.

I don't know how I could cross-record from one transport to the other. I suppose I could de-solder the L/R record head wires and reverse them on one transport?

I just connected a source to the L/R inputs and pressed record without a tape inserted. Both LED meters moved and I got audio from both L/R outputs, if that means anything.

[JimBanville]

Re: Both right channels dead on dual deck JVC KD-W110 cassette player

Is there a schematic/service manual for it? Can you cross-record, that is from R ch on one deck to the other? Just to see if there is internal R ch activity, compared to Line Out.
No R ch in both decks likely means the REC-PLAY switch circuitry or further downstream is the problem. If it's only one channel in one deck, easier to track down.
I would go to the tape head preamps IC801, IC802 and confirm there is signal output there.

Wild guess is after those tape-head pre-amp IC's is the electronic switching CD4066B's IC803, IC804 which I would suspect.
Write down DCV measured at their 14-pins. It's easy to see the R and L circuits, take comparison readings between channels, to see if a mux shorted in the IC.

Here are the voltages I got from IC 801 & IC 802 (results were very close) from pin 1 to pin 8...
1.3 & 1.3
.8 & .7
5.3 & 5.5
13.6 & 14.3
0 & 0
4.5 & 5.4
.7 & .7
1.3 & 1.3

[JimBanville]

Re: Both right channels dead on dual deck JVC KD-W110 cassette player

Is there a schematic/service manual for it? Can you cross-record, that is from R ch on one deck to the other? Just to see if there is internal R ch activity, compared to Line Out.
No R ch in both decks likely means the REC-PLAY switch circuitry or further downstream is the problem. If it's only one channel in one deck, easier to track down.
I would go to the tape head preamps IC801, IC802 and confirm there is signal output there.

Wild guess is after those tape-head pre-amp IC's is the electronic switching CD4066B's IC803, IC804 which I would suspect.
Write down DCV measured at their 14-pins. It's easy to see the R and L circuits, take comparison readings between channels, to see if a mux shorted in the IC.

Here are the results of IC 804 and 803...
9.7/9.7/9.7/9.7/.4/.4/0
13.2/12.7/12.7/9.7/9.7/9.7/9.7

9.7/9.7/9.7/9.7/12.7/12.7/0
13.2/.4/.4/9.7/9.7/9.7/9.7

[JimBanville]

Re: Both right channels dead on dual deck JVC KD-W110 cassette player

Here are the results of IC 804 and 803...
9.7/9.7/9.7/9.7/.4/.4/0
13.2/12.7/12.7/9.7/9.7/9.7/9.7

9.7/9.7/9.7/9.7/12.7/12.7/0
13.2/.4/.4/9.7/9.7/9.7/9.7

Those figures above are arranged where the first number on the first line is pin#1. So it's at the top left corner of the chip as viewed from the bottom of the pcb board. The figure below that pin #1 figure is the first pin on the bottom row of pins. The rest of the figures are arranged in the order in which they appear based on the physical layout of the chips.

[redwire]

Re: Both right channels dead on dual deck JVC KD-W110 cassette player

Still a little confusing on the pin numbers, I take it to be:

CD4066	IC804	IC803
Pin 1	9.7	9.7
Pin 2	9.7	9.7
Pin 3	9.7	9.7
Pin 4	9.7	9.7
Pin 5	0.4	12.7
Pin 6	0.4	12.7
Pin 7 GND 0	 0
Pin 8	9.7	9.7
Pin 9	9.7	9.7
Pin 10	9.7	9.7
Pin 11	9.7	9.7	
Pin 12	12.7	0.4
Pin 13	12.7	0.4
Pin 14 +VDD 13.2 13.2

Sometimes a bad IC will give a bad DC voltage on it's pins.
The DC voltages look OK. If you have a scope or signal tracer, going through the audio path will be the fastest way to troubleshoot. What do you have?
You can try Record as well, see if the R ch makes it to tape.

What is the part # on the head preamps IC801, IC802? Although the voltages look pretty matched between channels.