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 1 
 on: Today at 09:57:41 AM 
Started by Tennerondack - Last post by Tennerondack
Well Phil I return with big  ??? .
I finally got a few minutes. Put the power and preamp boards on top of the case, connected everything fired it up and everything worked. ?!?!
Maybe I jarred the right physical connection.
I' ll take it  :tu: Now I will have to check out sound quality, I may be back.
So far even lucking out, many thanks !

 2 
 on: Today at 05:22:35 AM 
Started by maxkriz - Last post by maxkriz
Much appreciated, thank you sir!  and a happy X-mass.

 3 
 on: December 11, 2018, 09:02:10 PM 
Started by maxkriz - Last post by dmeek
Here it is:


 4 
 on: December 11, 2018, 12:00:22 PM 
Started by maxkriz - Last post by g1
I have only seen for the IC100 :  https://www.ssguitar.com/index.php?action=dlattach;topic=4500.0;attach=8135;image
For the 'L' version, I think you would have to buy it from maj electronics.

 5 
 on: December 11, 2018, 08:49:54 AM 
Started by maxkriz - Last post by maxkriz
Hi there, will appreciate anyone sharing this as I could not find it on the web.
Got a sick HH IC100L that I'm trying to fix.
Thanks in advance
Max

 6 
 on: December 07, 2018, 02:57:06 PM 
Started by sewage666 - Last post by Used.Benz.Parts
Hi again,
Had some free time this morning, so I got the PCB (with the pots and inputs on it) out of the case and ohmed out the 0dB, -15dB, Effects Send, and Return jacks ... and they were all high resistance due to corrosion on the contacts.
Got ‘em cleaned up with a small file and contact cleaner, checked the tension on ‘em with the patch cable (making sure they opened and closed - several times), and rechecked the resistance: 0.40 ohms on ‘em all.
Put it all back together...

It works. Still a little crackle from the Squier due to patch cord contact at the output of that bass, but the Dean sound comes through nice and clear.

Guessing the years of use before I got my hands on it was the culprit.

Thank you guys so much for your help. I really didn’t know where to start, but now she’s up n running and I’m happy.

Thanks!

 7 
 on: December 06, 2018, 08:59:01 AM 
Started by Tennerondack - Last post by Tennerondack
Thanks Phil you are correct I have limited understanding but catch on quickly.

Your help is greatly appreciated. I am gradually learning.
I am going to get a signal injector and have at it.

Many thanks.    T .

 8 
 on: December 06, 2018, 06:51:34 AM 
Started by Tennerondack - Last post by phatt
Yes that Schematic looks a lot closer.
OK check for voltage at all the power supply nodes on preamp.
Power runs up the right hand side of schematic so just find those voltage drop resistors on the PCB and check you have supply on all those points.
If they all check ok then start checking if you have signal.

(I'm assuming you have limited understanding of how these things work)

Without a signal injector just use an insulated driver and touch each output while powered up.
You have 3 channels so start at the outputs and work back towards inputs.
Top ch OUT is top right at the junction 2/25 cap and 10k resistor.
if there is continuity then you will hear a crackle through the speaker.

Then work back towards input till you have no crackle.
As you may note Ch1 has 3 stages made up of two BJT pairs and input has 3 BJT.
Notice how each of those 3 stages have a Capacitor on input as well as Output.
They isolate the DC of each transistor stage from the AC signal.
You can safely touch the AC points without damaging the DC inside each pair of BJt's
So the first 3 transistors are DC (Directly Coupled, no caps between them)
but after Q3 of stage 1 you have a Decoupling Cap then the AC signal runs through the middle control before it passes into stage 2.
touching any of those AC points will make a noise if it's working.
Just work along the signal path till you find where the there is no sound.

All of this assumes the power amp is actually working. I'm not sure if that has been established yet?

If not then with preamp disconnected tap the power amp signal input and you should hear a little noise through the speaker.
Better still connect an mp3 player or any audio signal into the power stage to make sure it does deliver clean signal through the speaker. You will have to improvise a connection for that. maybe wise to put a plastic tube over the power pin for that test.

Your preamp is classic discrete design (each stage decoupled) while the power amp section is DC (Direct Coupled) notice how the power amp has no caps between each transistor.
When looking at a schematic you are really looking at 2 separate but interconnected circuits.
There is the DC path (power supply) which runs (in this case) from top to bottom, power rail on top and Common/Ground on the bottom. while the AC path (Signal you hear) runs left to right.
The basic concept is that you have to setup all the DC stuff so that the AC signal gets amplified.
If the DC stuff is wrong you get little or no signal or really bad distortion or nothing.

A simple way to understand Amplification is;
The AC signal floats on a DC voltage potential.
hope that helps a bit.
Phil.

 9 
 on: December 05, 2018, 01:19:15 AM 
Started by ilyaa - Last post by Jazz P Bass
There are a bevy of class d amps available on the net.

Small & simple.

Pick one that utilizes the +40/ -40 Vdc supply that you have.




 10 
 on: December 04, 2018, 09:01:36 PM 
Started by Tennerondack - Last post by Tennerondack
I heard from PV this is what they sent.
Now that the power ampseems functional, here is the next issue.
I connect the preamp, can detect 42 volts getting to the board, but get no audio output turning the various pots, whether or not an instrument is plugged in
I have checked all physical connections and used deoxit, etc.

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