Pioneer CT-F7171 issues

[mbates14]

I picked up a CT-F7171 off the curb the other day.

The transport system works great. But the audio system does NOT.

Anyone have a servicemanual or schematic?

When you try and play a tape, itll play but there is no sound. and there is a constant thumping/slow motorboat type sound.

The more you turn the output up, the stronger it gets, and the more it deflects the VU meter. and the pot sounds kind of scratchy, so that tells me the final output stages arnt where the noise is comming from.

only does this in play mode.

If i go into record mode, it sounds like a cheap pocket radio not tuned to a station. just constant snow/static sound. But i can BARELY hear some audio from the recording source comming through. But you cant turn the record volume up on the deck without the static sound blowing your eardrums out.

itll crackle for a little bit when hitting record, then it settles down to that static. also one channel has a little bit more audio creeping through than the other.

Any ideas?

 

[rotovator]

IIRC that deck is fully mechanical, even the audio board has a mechanical contacts part that changes signal path when going from play to record.

Make sure it is not dirty inside, clean it with some appropiate product.
If it doesn't work, you'll have to get the service manual, get a oscilloscope or a multimeter (would do the jobs sometimes) and follow the signal path to find where it is the fault

 

[TWTRTECH]

Yes, most likely a very dirty rec/play switch ass'y. Plus you would most likely need to clean all the controls and switches.

 

[mbates14]

that was the first thing i tried. was cleaning out that rec/play switch.

it improved the record monitor alot, but still had the hiss

Then the playback worked very good for a little bit. I took the mech apart to change some belts and relube it. Tried it again, same thing. pulsating sounds with no audio on the playback. tried to reclean the switch. nadda.

 

[Trower]

Might try and recap it as well as clean everything agian:yes:

 

[StanleyM]

Hi everyone, I also have a CT-F7171, I was replacing belts and cleaning. I lifted up the dolby processor assembly board to clean. When I went to secure it back down I accidentally cracked a diode, there are 3 screws that secure to the chassis. This diode is located on the right channel side right under the 3rd screw, which is in the middle of the board. I just want to know what the values are so I can replace it. I checked the same diode on the left channel, there are no markings and it is glass. If anyone can help it wold be appreciated.

 

[StanleyM]

OK I believe I have the diode in question from below it looks as if it is diode 205 is the one I damaged. I looked at which way the Anode is pointing on the board and on this snap shot. It looks as if D203-D206 are the same. I looked at the P/N and found it was made by Hitachi but is no longer made. I put the leads across the diode and got 8.95k and .291VDC.

 

[rikardo]

Hi mbates14, I just picked up a ct-f7171 that sounds like yours... pretty much the same issues btw. So i was curious about the fix you came across in the end (if any) ? thanks