Pioneer SDP5073 remote not working

[James Sweet]

I think this is the last of a long list of problems this set had. Remote
itself is fine, works with a P5075, remote sensor seems to be good as well,
I measure a voltage change at the main board where the front panel plugs in
when any button on the remote is pressed. No response from the set though,
none of the functions work. This is a problem that I've never encountered
before so I'm not sure how to proceed. I'm *so* close to having this thing
finished!

 

[JURB6006]

Some Pioneers have a chip in the front panel which is basically a "remote
emulator". If the output is stuck or noisy it can cause this. IIRC, if you
remove the chip and the remote works, the chip is at fault.

This is a code 135 on a Zenith MBR4300 series IIRC, of course there are others.

Over 90% of the time in a set with that architecture, if the remote doesn't
work it's the remote, you need to try another one.

The only other thing it could be is the IR detector itself. Luckily, Pioneer
isn't bad with parts, just find out which part.

JURB

 

[Leonard Caillouet]

Some Pioneers have a chip in the front panel which is basically a "remote
emulator". If the output is stuck or noisy it can cause this. IIRC, if you
remove the chip and the remote works, the chip is at fault.

This is a code 135 on a Zenith MBR4300 series IIRC, of course there are others.

Over 90% of the time in a set with that architecture, if the remote doesn't
work it's the remote, you need to try another one.

The only other thing it could be is the IR detector itself. Luckily, Pioneer
isn't bad with parts, just find out which part.

JURB

Could be something completely unrelated keeping the micro busy if the front
panel functions don't work.

Leonard

 

[James Sweet]

Could be something completely unrelated keeping the micro busy if the front
panel functions don't work.

Leonard

Front panel functions *do* work, however I'm voting for the something
keeping the micro busy theory or something along those lines. I have a P5075
which is virtually the same set that works fine. I pulled the left chassis
with all the small signal stuff and stuck it in the 5073, remote works fine
so I know the remote, front panel, wiring, and other associated bits are
fine. Curiously, when plugged in with that chassis nothing happens until I
hit the power button, but plug it in with the original and the set turns on
briefly and then back off again, after that it behaves normally other than
not responding to the remote.

I even scoped the plug on the chassis and found the remote signal, it looks
normal to me, unfortunatly though it snakes into a jungle of components
burried under a heatsink towards the back of the board. This board is
connected to the rest of the set through some very short cables making it
virtually impossible to do any probing with the set operating.

As an aside, does anyone know the correct method for measuring the HV? I
have a HV probe, but there's a warning not to lift the anode caps to check
HV but to refer to the service manual (which I wish I had) for the
procedure.

This repair has been my arch nemesis, I've never come across one so
involved, but I've come this far, I can't give up now.