quattro Voice Synthesiser

Mart · 18-04-17, 08:17 PM

Hi All, I was wondering if you could help me trouble shoot my voice synth challenge.

I have an '86 WR with a voice box part 857 907 399E. She's never spoken in my ownership and I'm determined to get her going. The wiring loom looks good and I have checked the speaker wiring - all good there.

Reading through the Isham Research bible, it all corresponds. I can confirm voltage coming into pin 30 (power) when the ignition is on, and I see voltage on pin 26 when the auto check button is pressed. However.. pin 27 (dashboard chassis ground) seems to be carrying approx 8v and there is never any voltage on pin 25 (ignition switch).

Unfortunately I don't know whether these readings are correct or not, or even if the box is correctly functioning; I have too many known unknowns (I'm sure there a few unknown unknowns lurking also).

If anyone can help me troubleshoot and or recommend some one who can help test these boxes, it would be hugely appreciated.

Given the box location, it's not something that can easily be swapped out of another car.

Any thoughts or suggestions would be greatly appreciated, this one has me scratching my head a little...

Hanuman · 19-04-17, 09:57 AM

Does the fault warning light come on? Yellow triangle, bottom left side of the various annunciators, adjacent to the ABS light?

If not, is it because the bulb is missing, or because the function doesn't work?

Voice output.
The voice box has an internal relay that simply changes the source for the right speaker from the stereo (no fault being reported), to the internal voice synth (chime, then aural warning)

After 30odd years, it's not a surprise if the relay is not working well. Could just be dirty contacts.

In a quiet car, with a working synthesiser, you can (just) physically hear the relay click when there is a fault warning.

A common error in car stereo upgrades is to completely or conveniently forget that the dash speaker is used for the synth.

Mart · 19-04-17, 10:39 AM

Hi Hanuman, Thank you for the response.

There is no triangle warning light that comes on - but the bulb does work, because if I connect the two round 3-pin connectors (T3b/T3c) which I believe should only be connected if there is no synthesiser then the warning bulb (and handbrake warning bulb) come on.

I have checked the speaker wiring and it looks to conform correctly - I can trace it into the box and the output from the box through to the speaker - If I unplug the box, the speaker stops working which further supports the theory. Interestingly it's the front right speaker which is hooked up however there is no evidence in that this has been changed.

As per your thoughts, I think I'll take another look at the relays just in case.

jimh · 19-04-17, 06:44 PM

If the yellow warning triangle never lights (but the bulb is ok), like you said, then there is probably no power to the voice box.
When you measured 8V on pin 27, was the voice box plugged in?

Measure the Voltage on pin 27 with the voice box plugged in, and also with it unplugged.
If it measures ~8V with voice box plugged in, but 0V(ish) when unplugged, then the ground wire is not connected to ground. Either trace it and find the break, or run a fresh ground wire from chassis to pin 27.

Pin 25 I think only sees Voltage when cranking the engine.

jimh · 19-04-17, 06:46 PM

Or just follow the wire from pin 27, and if it doesn't go anywhere, connect it to ground!

Mart · 19-04-17, 08:01 PM

Thanks JimH,

So I have tried a couple of extra things.... I slid the cover off the voice box and plugged it in and when the ignition is switched on, all 3 relays flick. If I manually flick the relays then two cut the sound to the speaker (I guess one should and the other is engaged for the speaking.

I'll need to try and get a clearer view of the Isham Research wiring - PIN 27 seems to be powered from the box - as per your suggestion Jim, I checked voltage on PIN 27 plugged in (~8v - actually showing closer to 9) and unplugged (0V) A continuity check of this wire to earth showed there was none, so trying a direct link to earth produced no positive result - I probably need to be careful here as although tiny ampage I was effectively shorting something out ...

The up shot is no huge breakthrough but good to see all the relays flick when the ignition is switched on.

If anyone has a WR and would be happy to recieve and plug in the box I have, I'd be willing to give that a go also (happy to trust in fellow quattro owners)

Mart · 19-04-17, 09:17 PM

So looking at the Isham diagram pin 27 (brown wire) goes into the T3b/T3c plug which needs to be unplugged with cars that have the synthesiser which mine does - so looks like it should be good....

After an hour with the wiring diagram (and going slightly cross-eyed), its starting to feel more likely to be the box as there is no obvious issue.

Quick question with those who have a working box - do you ever see the warning triangle light up (if you have'nt connected the 3-pin plug?

Mart · 19-04-17, 09:28 PM

Actually forget that last question, I can see it does from PIN 29, I'll need to do some more wire tracing to confirm it does on mine....

jimh · 20-04-17, 08:56 PM

Ok, it seems that pin 27 is not the power ground for the voice box, but is connected to ground if T3 is plugged together (which it shouldn't be in your case). I wouldn't worry about shorting pin 27 to ground damaging anything as that's what happens if T3 is plugged together anyway.

The yellow warning light is controlled by the voice box.
If the box is powered up and working (regardless of whether the speakers are connected or if the voice output actually works), the yellow warning light should come on when you start the engine, and go out after you press the brake pedal for the first time - it should then come back on if any faults are detected.

Just been looking at diagrams and been comparing '86 diagrams with '85 (my car). For the '85 model year, pins 18 & 27 are shown on the diagram as going to T2f (a 2 pin connector behind the dash which I assume should be connected). The '86 model year diagram shows these going to T3 (a 3 pin connector behind the dash that I think is the one normally left disconnected).
I find it strange that '85 expects these to be connected to ground, but '86 doesn't (even though they have the same 3 pin connector disconnected behind the dash).
Also, I cannot see where else the '86 voice box gets it's main ground connection.
Makes me think there is an error in the diagram.
The diagram shows pins 18 & 27 connected together, and then to T3. Can you verify that?
I think they might have drawn that up wrong and pin 27 should be permanent ground as shown in the '84 diagram - like adding pin 18 & T3 confused the diagram.
Surely it should have a permanent ground connection somewhere?

The easiest way to disable the voice box is to remove power (or ground) from it. It can be done (sometimes accidentally) by disconnecting the speaker wires, but that would leave the yellow warning light on if there was any fault, so you'd have to disable the lamp somehow too.

Mart · 21-04-17, 06:49 AM

Thanks JimH,

The chassis ground is not part of the T3b/T3c connector but does route to another T3 connector (yellow in my case) which is all plugged in and original. I have continuity from the box to this connector, and see the +8v on the wire (rightly or wrongly) - I can only assume there is a PD delta measure which takes place on this wire. The wire disappears off under the carpet along with the diff actuator pipes. Short of removing the dash and carpet the car follows the wiring diagram and the wiring is not fiddled with; I know that fundamentally there is power going to the box and it is earthed (relays clicking in/ out gives me that confidence).

Thank you for clarifying the behaviour of the warning light - that's useful to know. I think my viable next step is to clarify if the box itself actually works and remove that variable.

Thanks again for all your help, I'll keep you updated as to progress - and if anyone knows a knowledgeable repairer of voice synthesizers please do let me know

19-04-17, 09:57 AM	#2
Hanuman Trickster Classic Audi Club Member Join Date: May 2009 Location: Heckling from the cheap seats, Phnom Penh, KoW Posts: 7,006	Does the fault warning light come on? Yellow triangle, bottom left side of the various annunciators, adjacent to the ABS light? If not, is it because the bulb is missing, or because the function doesn't work? *Voice output.* The voice box has an internal relay that simply changes the source for the right speaker from the stereo (no fault being reported), to the internal voice synth (chime, then aural warning) After 30odd years, it's not a surprise if the relay is not working well. Could just be dirty contacts. In a quiet car, with a working synthesiser, you can (just) physically hear the relay click when there is a fault warning. A common error in car stereo upgrades is to completely or conveniently forget that the dash speaker is used for the synth. __________________ I wish they would keep the damned Chinese away now that I can go home, so that I can enjoy Fish amok and a draught Angkor

19-04-17, 10:39 AM	#3
Mart Newbie! Join Date: Sep 2016 Posts: 13	Hi Hanuman, Thank you for the response. There is no triangle warning light that comes on - but the bulb does work, because if I connect the two round 3-pin connectors (T3b/T3c) which I believe should only be connected if there is no synthesiser then the warning bulb (and handbrake warning bulb) come on. I have checked the speaker wiring and it looks to conform correctly - I can trace it into the box and the output from the box through to the speaker - If I unplug the box, the speaker stops working which further supports the theory. Interestingly it's the front right speaker which is hooked up however there is no evidence in that this has been changed. As per your thoughts, I think I'll take another look at the relays just in case.

19-04-17, 06:44 PM	#4
jimh Grown up member Classic Audi Club Member Join Date: Dec 2008 Posts: 122	If the yellow warning triangle never lights (but the bulb is ok), like you said, then there is probably no power to the voice box. When you measured 8V on pin 27, was the voice box plugged in? Measure the Voltage on pin 27 with the voice box plugged in, and also with it unplugged. If it measures ~8V with voice box plugged in, but 0V(ish) when unplugged, then the ground wire is not connected to ground. Either trace it and find the break, or run a fresh ground wire from chassis to pin 27. Pin 25 I think only sees Voltage when cranking the engine.

19-04-17, 06:46 PM	#5
jimh Grown up member Classic Audi Club Member Join Date: Dec 2008 Posts: 122	Or just follow the wire from pin 27, and if it doesn't go anywhere, connect it to ground!

19-04-17, 08:01 PM	#6
Mart Newbie! Join Date: Sep 2016 Posts: 13	Thanks JimH, So I have tried a couple of extra things.... I slid the cover off the voice box and plugged it in and when the ignition is switched on, all 3 relays flick. If I manually flick the relays then two cut the sound to the speaker (I guess one should and the other is engaged for the speaking. I'll need to try and get a clearer view of the Isham Research wiring - PIN 27 seems to be powered from the box - as per your suggestion Jim, I checked voltage on PIN 27 plugged in (~8v - actually showing closer to 9) and unplugged (0V) A continuity check of this wire to earth showed there was none, so trying a direct link to earth produced no positive result - I probably need to be careful here as although tiny ampage I was effectively shorting something out ... The up shot is no huge breakthrough but good to see all the relays flick when the ignition is switched on. If anyone has a WR and would be happy to recieve and plug in the box I have, I'd be willing to give that a go also (happy to trust in fellow quattro owners)

19-04-17, 09:17 PM	#7
Mart Newbie! Join Date: Sep 2016 Posts: 13	So looking at the Isham diagram pin 27 (brown wire) goes into the T3b/T3c plug which needs to be unplugged with cars that have the synthesiser which mine does - so looks like it should be good.... After an hour with the wiring diagram (and going slightly cross-eyed), its starting to feel more likely to be the box as there is no obvious issue. Quick question with those who have a working box - do you ever see the warning triangle light up (if you have'nt connected the 3-pin plug?

19-04-17, 09:28 PM	#8
Mart Newbie! Join Date: Sep 2016 Posts: 13	Actually forget that last question, I can see it does from PIN 29, I'll need to do some more wire tracing to confirm it does on mine....

20-04-17, 08:56 PM	#9
jimh Grown up member Classic Audi Club Member Join Date: Dec 2008 Posts: 122	Ok, it seems that pin 27 is not the power ground for the voice box, but is connected to ground if T3 is plugged together (which it shouldn't be in your case). I wouldn't worry about shorting pin 27 to ground damaging anything as that's what happens if T3 is plugged together anyway. The yellow warning light is controlled by the voice box. If the box is powered up and working (regardless of whether the speakers are connected or if the voice output actually works), the yellow warning light should come on when you start the engine, and go out after you press the brake pedal for the first time - it should then come back on if any faults are detected. Just been looking at diagrams and been comparing '86 diagrams with '85 (my car). For the '85 model year, pins 18 & 27 are shown on the diagram as going to T2f (a 2 pin connector behind the dash which I assume should be connected). The '86 model year diagram shows these going to T3 (a 3 pin connector behind the dash that I think is the one normally left disconnected). I find it strange that '85 expects these to be connected to ground, but '86 doesn't (even though they have the same 3 pin connector disconnected behind the dash). Also, I cannot see where else the '86 voice box gets it's main ground connection. Makes me think there is an error in the diagram. The diagram shows pins 18 & 27 connected together, and then to T3. Can you verify that? I think they might have drawn that up wrong and pin 27 should be permanent ground as shown in the '84 diagram - like adding pin 18 & T3 confused the diagram. Surely it should have a permanent ground connection somewhere? The easiest way to disable the voice box is to remove power (or ground) from it. It can be done (sometimes accidentally) by disconnecting the speaker wires, but that would leave the yellow warning light on if there was any fault, so you'd have to disable the lamp somehow too.

21-04-17, 06:49 AM	#10
Mart Newbie! Join Date: Sep 2016 Posts: 13	Thanks JimH, The chassis ground is not part of the T3b/T3c connector but does route to another T3 connector (yellow in my case) which is all plugged in and original. I have continuity from the box to this connector, and see the +8v on the wire (rightly or wrongly) - I can only assume there is a PD delta measure which takes place on this wire. The wire disappears off under the carpet along with the diff actuator pipes. Short of removing the dash and carpet the car follows the wiring diagram and the wiring is not fiddled with; I know that fundamentally there is power going to the box and it is earthed (relays clicking in/ out gives me that confidence). Thank you for clarifying the behaviour of the warning light - that's useful to know. I think my viable next step is to clarify if the box itself actually works and remove that variable. Thanks again for all your help, I'll keep you updated as to progress - and if anyone knows a knowledgeable repairer of voice synthesizers please do let me know