Teac V-95RX -- No Left Channel Output

[SSowner]

This is only my second post on AK, I mostly read everyone's posts to solve issues with my audio gear. Thank you everyone! I have researched for a couple of days for ideas on how to repair a V-95rx I own. It has no left channel output at the RCA jacks or the Phone jack. Any ideas would be appreciated. What I have done so far:

1. Downloaded Service manual
2. Checked "Output" Pot -Good < 5ohms between RCA output and Point 32 on R/P circuit board
3. Removed Cleaned/polished the Solenoid actuated slide switches S101 and S102 (FWD /REV and RP and reinstalled same.
4. Flipped P1(from Head) on R/P circuit board-- problem did not follow, still no left channel. Normaled up P1.

Thanks ahead of time!

 

[hdrobien]

You would need a scope to follow the signal from the heads to the outputs.

If you have both channels on the meters, it could narrow the search area.

 

[SSowner]

You would need a scope to follow the signal from the heads to the outputs.

If you have both channels on the meters, it could narrow the search area.

Thanks hdrobien-- No display on left channel meter even after flipping P1 (swapping L&R input to R/P CC from head). I will try and borrow a scope. Anyone else? Checked TP L and TP R with tape playing, both show ca 380-390mv.

 

[hdrobien]

Ok, so you need to find the service manual and follow the circuit from the TP to the output.

S104/S105 may be guilty.

 

[SSowner]

Thanks for the input. Sorry for the late reply. Have not tested either yet. S101 and 102 were not too bad though. We'll see. Thanks Again

 

[skywavebe]

These things can be a pain to work on but the solenoid switches can be a very big problem in that spray cleaning may not be enough. This is why I use Curt Jacobs retrofit switch for the X2000R where it has a like type switch that is also unreliable. I have repaired this in the past both at my own shop and some at Teac when I was there in the 80's.
The V-909RX was an improved model of the same kind of device with 4 channel heads but out of the decks that I approve of that were auto reverse the R-888X was the one that was much much better in design with a three head rotating function but that the stops were ceramic that held good alignment. 4 channel heads rarely were in good alignment in both directions- I got one to do it in 3 hours work but it was done in adjusting the tape path run to do it. The $14 4 channel head was not all that precise of a device or part.

 

[skywavebe]

You don't need to reverse plugs and that. The lack of signal through a channel can be done using the buzz test as in touching the head connector with a screw driver and seeing if output is at any amps after that. It is good to keep an eye out of 10V caps of the Marcon type as I have seen them fail in many types of equipment including NAD and Teac . I pulley 16 out of the Tascam 48 when some of them shorted- they were 220uFd 16V types but Marcon again.

 

[SSowner]

Thanks for the replies Sam! I disassembled and polished the contacts in both solenoid switches. They were not too bad, black and gray in spots but shiny where the contacts met. I will try the buzz test and check those caps. With the holidays i will be pulled away from the work bench often, I end up starting from the beginning every time. LoL. During my Electronic Maintenances time in the 80s(Army) I would do binary searches, test the circuit halfway through-- Bad reading problem was in first half, good reading problem in the send half. Is there a half way point with the v-95?

 

[duncan]

I'm assuming you have tried all the noise reduction modes, none/dolby/dbx, and none make a difference.

Any chance Q103 is shorted? What happens if you float the collector on it?

 

[garf666m]

Don't know if it's same issue, but i am able to get back sound on all channels when playing with output volume and/or the type selection (norm/cr2/metal). I guess in my case i need to deoxit these contacts