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joust

Member Since 02 Dec 2004
Offline Last Active Today, 04:04 PM
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Posts I've Made

In Topic: How to troubleshoot efficiently?

Today, 04:05 PM

Hello Jeff, (Note : You haven't responded to my PM...)

I won't go into the amplifier troubleshooting guide now, we can do that in PM. Now, as for your K2 :
First thing : The symptom described above, was this the original symptom? Can you confirm you have the manual? There are a lot of flow charts inside!

OK. Now you'll have to let me know your different voltages : You should have a +15V, a -13V (!), and +/- 105V (around) for the HV rails.
Since you removed the output modules, might as well refurbish the beasts! Verify the filter caps, and if possible, measure them. (Note : There are high voltages present! It would be important to discharge the output rails before attempting to remove or repair the K2. The owner's manual explains how to use TP1. section 5-2 in the manual).

I have found numerous times that C23 and C24 (-13V circuit, 100uF 25V) may have changed value; I replace them as matter of fact (especially if the units date code is older than 2002).

So now you have issues with the output boards : Are both defective?? How are the Silpads? Hopefully, you have been very gentle with them! They isolate the positive HV from the chassis. If holes are discovered, the Silpad should be replaced; You could use small bits of Kapton tape to cover these holes.
Verify the buffer ICs (34151) and the HS optos (2601, 2611), since the 5V regulator died.

You mention that you replaced U51 : This is not a 12V regulator but a 5V regulator.

As for the IT6000, let's do it when you'll be evaluating it.

Peace.

Alain

In Topic: What's Z1 in a MA5002VZ?

21 April 2014 - 08:42 AM

You don't have this symptom in Bridge mode?
If not, then Ch2 preamp may be at fault, since the Ch2 preamp is kind of 'bypassed' in Bridge mode.
Note : 185mV is not extreme. I believe the amp will work fine even with this offset.
Note : the owner's manual states that if an [out of tolerance] output offset is present, to verify the ODEP circuit.

Hope this helps!

Alain

In Topic: What's Z1 in a MA5002VZ?

17 April 2014 - 08:05 AM

Hello Jeff,

I did find Z1 on a Terminator diagram (cpn 102396). Z1 is a 'ground lift' link, possibly installed for grounding issues.
If Z1 is installed, the main ground (also Common output) is connected to chassis ground (usually, the source AC ground).

If Z1 has flared, it is possible you have an issue with your grounds.

Alain

In Topic: ZeeVee Delay Issues

17 April 2014 - 07:54 AM

Hello Wally,

As Avi has mentionned you can't 'advance delay' in the future.
Since the CDi DSP 'latency' is approx. 1.11ms, there should not be any audio issues with the CDi, per se.
So, my conclusion is that the audio delay is caused by the ZV system. Perhaps, updates to the ZV system might fix the lipsync issues.

Alain

In Topic: CTS4200a dead

15 April 2014 - 01:09 PM

Hello ATPP,

Fantastic! I'm glad you go it working!

A.