2254C build/support thread

[duantro]

Hey MrBlomski
I can't tell for sure, but it looks like the label on your back transformer is 9045, which I believe is backwards. Look at my pic here. I have 9045 in the other position.

I finally got this thing put together. It fires up with no black smoke!!
Tomorrow I will take it to the studio and see how it sounds. I can't wait.

Edit: The photo didn't copy. The post is #643.

So could I switched and reversed INTR1 with INTR2 ?!!??!? Thats a double suck

I trace the carnhill pinouts with a multimeter and came with the following results

INTR1 = VTB9045 for low level microphone input
INTR1 Pin1 Molex PRI + = Pin 7 VTB9045
INTR1 Pin2 Molex PRI - = Pin 10 VTB9045
INTR1 Pin3 Molex GND = Pin 11 VTB9045
INTR1 Pin4 Molex SEC + = Pin 2+3+4 VTB9045
INTR1 Pin5 Molex SEC - = Pin 5 VTB9045

INTR2 = VTB9046 for line level input
INTR2 Pin1 Molex PRI + = Pin 2 VTB9046
INTR2 Pin2 Molex PRI - = Pin 5 VTB9046
INTR2 Pin3 Molex GND = Pin 11 VTB9046
INTR2 Pin4 Molex Sec + = Pin 7 VTB9046
INTR2 Pin5 Molex Sec - = Pin 6 + 10 VTB9046
But youre INTR1 = VTB9046 and youre INTR2 = VTB9045

Yes, it looks like a double suck!
I believe it is:
INTR1: Input-line VTB9046, 31267, TF10016,...
INTR2: mic VTB9045, 10468, TF10015,...
I was going to say that you could just unplug the molex connectors and swap the tranny's but it looks like some solder removal time!

 

[MrBlomski]

And I have to short what kambo said at post #97 I see.
Hmmmz, why o why I looked over this SO !#$%%! IMPORTED PIECE OF MATERIAL

;D

 

[duantro]

I hear you, man. I remember being somewhat confused when I built these also. Hey, at least nothing may not have blown up!
If you are bored sometime look at the Fairchild pm670 thread ...150+ posts and tons of problems.

 

[MrBlomski]

Do I have to shorten the trannies if I solder them directly on the PCB?


9046 line in
primary :
short pin 3-4
connect 2(+) - 5(-) to molex

secondary :
short pin 8-9
connect 7(+) - 10(-) to molex
connect 6 to GRD molex

9045 interstage :
primary :
short pin 3-4
connect 2(+) - 5(-) to molex

secondary :
short pin 8-9
connect 7(+) - 10
6, ground molex
-------------------------------------------

EDIT: on The PCB is it shorted.

 

[duantro]

Do I have to shorten the trannies if I solder them directly on the PCB?


9046 line in
primary :
short pin 3-4
connect 2(+) - 5(-) to molex

secondary :
short pin 8-9
connect 7(+) - 10(-) to molex
connect 6 to GRD molex

9045 interstage :
primary :
short pin 3-4
connect 2(+) - 5(-) to molex

secondary :
short pin 8-9
connect 7(+) - 10
6, ground molex

This all looks correct. I'm not sure as for needing to short the necessary transformer pins when soldering directly to the pcb, as I used the molex connectors and shorted the pins on the transformers. I'd take a multimeter and check for continuity on the pcb connections that need shorting, for instance pin 3, and pin 4 on the primary pcb. This way you can confirm if you still need to short them, or if they are done so already on the pcb.

 

[MrBlomski]

Desolderd the trannies and put them in the right place.
Test connections and its a ok!
Put some juice on it check voltage, seems ok!

Put a 1 KHz test tone into the compressor, bypass works, i got sound,
Set compression in, sound is gone. again.
Check Hz on T1 line Pri + and - Sec + and - all got 1 KHz

Check on T2 no Hz or what so ever. T2 is not broken I checked.

So whats next? Anyone?

Edit: I hear noise when it is switched in and the noise becomes louder when I makeup the gain.

 

[duantro]

Desolderd the trannies and put them in the right place.
Test connections and its a ok!
Put some juice on it check voltage, seems ok!

Put a 1 KHz test tone into the compressor, bypass works, i got sound,
Set compression in, sound is gone. again.
Check Hz on T1 line Pri + and - Sec + and - all got 1 KHz

Check on T2 no Hz or what so ever. T2 is not broken I checked.

So whats next? Anyone?

Edit: I hear noise when it is switched in and the noise becomes louder when I makeup the gain.

Check all of your wiring, Molex connections, switches, and components for correct values. If you still strike out, then pull out the schematics and trace the signal with a scope or signal tracer, and see where it stops.

 

[r2d2]

somebody know if pcb are still available ?
peace.

 

[duantro]

I believe our pals at ramshacklerecording are putting in the effort to make some of igor's fine projects available soon. Im sure there will be a post here or in the white market when they are ready or toss them an email at gmail to get on their mailing list.

 

[prescott]

Hello!

Does anybody has a stereo PCB set for sale?

I'd like to buy

Thanks!

 

[prescott]

Ok, i've bought a set on the black market luckily...

Can someone help me to find the front panel corel file, that Igor mentioned before?

Thanks!

 

[duantro]

Ok, i've bought a set on the black market luckily...

Can someone help me to find the front panel corel file, that Igor mentioned before?

Thanks!

I don't have the files but,
I'd hit up Tat Parusha over at diyracked. That's where I got mine.
Also Dan's front panels in the White Market has them.

 

[MrBlomski]

Ok, somebody can help me out here please because I dont know where I am at the moment.
I do not have sound on the unit when I turn the comp IN.
I checked the +CV on the power supply and it is +3VDC
I also Trimmed the BIAS at 4.7 VDC.

So I am following the signal path.
Bypass, signal is going in and out.
Comp IN, no sound!
Checked signal path wit multimeter beep and the VCA section seems ok.
btw, can you hear the RELAY switching by ear if it's switched on/off?


EDIT:

Problem found, it where the bc214 transistors that where smoked because of the reversed placed carnhill transformers.
I replaced them with BC560C

EDIT2:

Had a hum, connected pin 2 from OPT_MTR to ground chassis, hum gone. Also described page 16.

 

[whomper]

Hi,

About to finish building a unit and my 1n4153 that I bought from futurlec.com look a little different from what I expected. They are orange with a blue stripe and measure on average 0.6v. As I had some issues with futurlec.com in the past, I wanted to check whether someone used the same batch of diodes.

Thanks

 

[whomper]

There's a strange problem with my unit that for some reason eludes me.

Connecting signal to any channel I get a quitter and distorted signal on the other channel's OUT although nothing is connected on its IN jack... ? As fast as I can tell, the only place where the two boards interact is at the power supply board.

Can you guys share some hints as to who to approach this strange issue?

 

[whomper]

There's a strange problem with my unit that for some reason eludes me.

Connecting signal to any channel I get a quitter and distorted signal on the other channel's OUT although nothing is connected on its IN jack... ? As fast as I can tell, the only place where the two boards interact is at the power supply board.

Can you guys share some hints as to who to approach this strange issue?

Ok, found my problem. I mistakenly connected OP_MTR pin1 and not pin2 to chassis, which caused distorted sound leakage between the two boards, as well as distort any single board by itself. Connected pin2 to chassis and all is great now!

Calibration was a little hassle and I eventually calibrated first board as much as I could and then tuned the second one to match the first. Tested in linked mode as well.

Great unit!

 

[Screamer]

Hello !

I need some help on my stereo 2254C (Igor). I would be really happy if someone could help me to resolved my problem. 

Power is okay 24V, All led and Vu meter is on, All transformer is connected and works (VTB9046, VTB9045, VTB9049. I tested by injecting an input signal on each.)
When my unit is bypass (switch), it's okay. Normal ....
but when my 2254 is on, I have a very big distortion on the 2 channels. Full distortion mix with input signal. Much more distortion that signal.

I think my problem is in the section "B183.110" (above the sidechain HPF on schematic).
I have approximately 21-23V on the primary of my output transformer  !!! I think this is the problem...

That is my tensions (on the 2 channels)
- Unit Power = 23,9V
- R7'' = 4,7V (Okay, I adjust the RV1)
- CPS''1 (+) = 22,7V (Okay, why not, I think is normal, There is just R44 10ohm before 24V)
- Collector of my 2N3055 (case of the transistor) = 21,3 V (very strange I think  ???)

And on the schematic (if I understand good) The primary output transformer is connected to CPS''1 (+) and Collector 2N3055, 22,7V and 21,3V (OP_TR1 and OP_TR2). I think is not normal.....

I hope that someone can check that tensions to help me 

And Idea ? (I spent a month to check all, no result)
Thanks.

(Sorry for my english)

 

[MrBlomski]

Did you try to caibrate the beast?

 

[Screamer]

The "beast" is too much noisy to be calibrated. Makeup at 0, always noise on output.
I can just calibrate only the RV1 with 4,7 V on R7''.

Thanks for your answer.

 

[Screamer]

Does anyone know the values of C19, R54 and R47 for the input transformer VTB9046 ?
Thanks