TIU sees AIU. AIU not working

Did you connect the "problem" AIU to the same connector to replace the working one to make sure it's not cabling?

gunrunnerjohn posted:

Did you connect the "problem" AIU to the same connector to replace the working one to make sure it's not cabling?

John,

 Yes, I made sure the only variable in my test was the AIU. Cable from TIU is the same.   I also hooked up a known working switch that works with the new AIU.

Perhaps a feature tiu reset or cycle tiu power . I'm not sure what info is stored in the tiu but I think it's only  custom sounds and the record /playback feature so a reset shouldn't delete anything.

What are using to power the tiu? fixed one  or  an aux power supply?

Gregg,

Perhaps a feature tiu reset or cycle tiu power 

The OP stated that he swapped the AIU for a known, good one and the problem went away. That indicates that the AIU is defective and no TIU reset or power cycle is going to cure it.

I'm not sure what info is stored in the tiu but I think it's only  custom sounds and the record /playback feature so a reset shouldn't delete anything.

That's correct.

Did it work at one time and then failed?

Did you peer into the AIU jack to verify the integrity of the connector "fingers" (or whatever you call them)?

Are you going to attempt a DIY repair?  It appears you're willing to go under the hood so if you have a voltmeter, a simple test which would reveal a lot is to confirm you have two key DC voltages within the unit.  Using the metal tab of the power supply regulator chip as ground (i.e., to black lead of voltmeter), do you read +12V DC (actually about +11.5V) and +5V DC on the indicated pins?  Obviously the unit must be powered/connected to the TIU.

Again, if you want to troubleshoot further, since you have 2 units, it would be useful to know what happens if you connect the "good" AIU downstream from the "bad" AIU.  In other words, TIU -> bad AIU -> good AIU.  Does DCS detect 2 AIUs?  Presumably the bad AIU is still bad.  But does the good AIU work with the bad unit in the comm path? 

Barry Broskowitz posted:

...

Te OP stated that he shaped the AIU for a known, good one and the problem went away. That indicates that the TIU is defective and no TIU reset power cycle is going to cure it.

I think you mean swapped?  In which case I'm not clear why this indicates the TIU is defective?  I'd say it's the AIU that's defective.

stan2004 posted:

Barry Broskowitz posted:

...

Te OP stated that he shaped the AIU for a known, good one and the problem went away. That indicates that the TIU is defective and no TIU reset power cycle is going to cure it.

I think you mean swapped?  In which case I'm not clear why this indicates the TIU is defective?  I'd say it's the AIU that's defective.

I think Barry just typo'd.     I understood him to mean the AIU is defective since I did a direct swap for the known good one and everything worked.

stan2004 posted:

Did it work at one time and then failed?

Did you peer into the AIU jack to verify the integrity of the connector "fingers" (or whatever you call them)?

Are you going to attempt a DIY repair?  It appears you're willing to go under the hood so if you have a voltmeter, a simple test which would reveal a lot is to confirm you have two key DC voltages within the unit.  Using the metal tab of the power supply regulator chip as ground (i.e., to black lead of voltmeter), do you read +12V DC (actually about +11.5V) and +5V DC on the indicated pins?  Obviously the unit must be powered/connected to the TIU.

Again, if you want to troubleshoot further, since you have 2 units, it would be useful to know what happens if you connect the "good" AIU downstream from the "bad" AIU.  In other words, TIU -> bad AIU -> good AIU.  Does DCS detect 2 AIUs?  Presumably the bad AIU is still bad.  But does the good AIU work with the bad unit in the comm path? 

Stan,

  Thank you very much.   I will pull out the multimeter and dig in this evening when I get home.   I appreciate the picture and the info on what to check.  I will also check the "fingers" in the jack to make sure nothing's bent.

It is an old AIU one that did work last time I used it about 8 years ago

That's one reason I bought a new one from a forum member.

As an aside, when I had it open I did look at those two caps and nothing seemed amiss; no bulging or leaking.

That power chip looks like the venerable 7805.   Do I assume if I'm not seeing correct voltage this is the place to start?

I have local store that stocks tons of them for less then a buck. I may go get a couple just to have.

Yeah, I'm not afraid to tinker/attempt with this unit since it's old, and I have a good working one now. I'm good with solder and circuit boards, I'm just not a tech by trade so I just need to know where to look

Thank you again!

Stan,

I think you mean swapped?  In which case I'm not clear why this indicates the TIU is defective?  I'd say it's the AIUthat's defective.

You're kidding, right? It was a typo.

I''ve reposted it to state:

The OP stated that he swapped the AIU for a known, good one and the problem went away. That indicates that the AIU is defective and no TIU reset or power cycle is going to cure it.

EscapeRocks posted:

That power chip looks like the venerable 7805.   Do I assume if I'm not seeing correct voltage this is the place to start?

I have local store that stocks tons of them for less then a buck. I may go get a couple just to have.

Correct, the venerable 7805 which is sold everywhere and relatively easy to replace with modest soldering skill.  But that's if you don't see +5V on the right (output) pin.  If you don't see +12V DC (or so) on the left (input) pin, then it's likely NOT the 7805.  Actually, this latter case would be good news since it means the +12V is not making it from the 6-pin connector so should be easier to track down/repair.

Barry Broskowitz posted:

Stan,

I think you mean swapped?  In which case I'm not clear why this indicates the TIU is defective?  I'd say it's the AIUthat's defective.

You're kidding, right? It was a typo.

 

Not kidding at all. 

The conversation at that point was about resetting the TIU configuration/software.  With modern electronics the ability of a host device (TIU in this case) to recognize and properly operate attached devices (AIU in this case) can be a software issue.  I can't count the number of cases where a host can detect something is attached but can't communicate with it...then attach a different but seemingly identical device and it works.  Come to find out it was some forward/backward compatibility issue because of a defective/incorrect software version or hardware revision on the host side (TIU in this case). 

But it was a simple typo, now corrected, and we're in agreement that David needs to focus on the AIU.

Okay, here are the test results:

1. checked jack pins on both TIU and AIU. All solid, none bent
2. checked the known good AIU with another cable.  Still works
3. that 2nd cable with bad TIU: still not working
4. getting 12.4vdc and 5.0vdc as described above.
5. connected TIU>Bad AIU>Good AIU.   reading 2 AIU's
6. good AIU does not work in this config
7. re-hooked good AIU by itself.  It works.

I must have really fried something years go

Bad luck.    But kudos to you for concisely summarizing the results.  In my opinion you'd need an oscilloscope to further troubleshoot the unit.  What's frustrating is, it's probably "just" one of those 50 cent IC chips that failed.  The dozen or so chips on the board are commodity/generic components, no custom programmed chips, no software to mess with, etc.

Hard to believe you could take it to a LHS repair shop and come out for less than, say, $50...and if you had to pay shipping both ways.  Given these are on eBay for, say, $75/$125 used/new, how does one decide what to do?  

Stan,

 I appreciate your assistance in this testing process.   Luckily I have the new one that is working just fine.

Thanks again!!