Alpine PDX1.1000 powers on, no audio (IR2010s HELP)

[mild2wild]

I was mistaken. I could have sworn that I saw a square wave on Pin1 but just after reinstalling the transistors but am not seeing that again afterwards. I can only say I made a mistake since that is not the case right now.

 

[Perry Babin]

Do you have 5v on the emitters of the transistors still. Initially, it won't be there (will be negative) but after a short mute delay, the voltage should go to 5v.

 

[mild2wild]

On the emitter of Q9701 I have 4.65v, and on the emitter of Q9702 I have -3.65v.

Edit: Now I have different voltages after turning off and on again. With 100hz signal at volume 35, I have -0.55v on Q9701 emitter, and -1.17v on Q9702 emitter.

The voltages on the base is also different. Q9701 -1.14v and Q9702 -1.73.

 

[Perry Babin]

The emitters will initially be negative then will transition to +5v. The time shouldn't be more than a few seconds.

If the voltage never goes to 5v on the emitters (try with no input), post the DC voltage on IC4502. Don't slip and short the pins.

pin 1 will change after a few seconds.

 

[mild2wild]

I just noticed IC4501 leg4 is damaged/missing. Would this be the cause of the malfunction?

IC4502
5.06
5.00
0.00
0.00
0.00

IC4501
0.00
5.04
0.00
Leg4 missing(pad leading to Q4501 reads 1.28v)
5.05

What is a replacement for Q4501 and Q4502?

 

[Perry Babin]

The part numbers are on the diagram.

Connect a jumper between the collector and emitter of Q4501. Does that give you drive on the collectors of the level shifters?

 

[mild2wild]

I can't seem to find anything relating to the part numbers in the schematic for IC4501/4502. Is that part obsolete?

So, I killed my USB scope. The probe fell, and the remote wire fell, and there was a spark...no more scope for a few weeks. Can you recommend an affordable scope option, under $100. I have gotten used to the vivid display of the USB scope, but they keep dying on me...

 

[Perry Babin]

The part may not be obsolete. Just rarely used and not widely stocked. An Alpine parts dealer will likely be able to get them.

If you have to have a digital scope, the OWON VDS1022I (<<< I is very important) is the only one I have significant experience with.

 

[mild2wild]

Does the isolation I in the OWON VDS1022I make it any safer to use in high voltage amplifiers/equipment, or is it simply a performance enhancement?

Can this oscilloscope be used to perform most, or any, amplifier repairs? Such as we have been doing in this thread?
Quimat Updated 2.4" TFT Digital Oscilloscope Kit with Power Supply and BNC-Clip Cable Probe Q15001 (Assembled Finished Machine): Amazon.com: Gateway

 

[Perry Babin]

The isolation allows you to measure drive signals that are referenced to rail voltage or are swinging rail-rail.

I don't know if that scope will work. The two cheap scopes that I know about are that owon and the DSO-138. The 138 is a toy that's only good for audio frequency use.

 

[mild2wild]

I am placing a Mouser order for a few amps, would it be a good idea to purchase various transistors, diodes, ICs, etc that are specified in the schematic?

I plan to purchase some anyway since I purchased another M1000 from eBay in hopes of learning something that may help with the 1000s I am currently already trying to repair. A few of the components are unavailable but maybe you can suggest some that may be prudent to have on hand as we continue to attempt this repair...

 

[Perry Babin]

I have worked on only a small number of the 1000s. Mainly FETs and driver ICs failed. Sometimes, the ICs between the level-shifting transistors and the drivers failed.

 

[mild2wild]

Purchased an OWON VDS1022I but am having the most difficult time with the USB driver. Do you have personal experience with setting this unit up? No matter what I do, I can't get the USB driver software to work.

UPDATE: finally got it to work, so I am ready to continue with the repair. Figured out anything with the M1000 since last post?

I purchased some replacement components for the PDX1000 and M1000, so let's see if any are necessary...

 

[Perry Babin]

What was I supposed to do? Your scope died when you were checking various points.

 

[mild2wild]

No problem, I will backtrack a few posts and recheck everything so as to be sure of current status.

Did you get your M1000 working? I remember you said an IC was bad...

 

[Perry Babin]

I'm not going to do any more with it. I purchased it for one reason and it served that purpose well enough.