Resistor Values for Aux Master Module

[Today Is The Day Official]

Hi Guys,

Well, the Cue amp saga continues. After my freakout last night with 2 bad headphone amps.

I bought another one that works, except the Cue Amps are not putting out. So, I took out the Aux 

Master Module (Cue 1 and 2 Master) and removed the 2 Small Cards with the buttons to select. 

On The Circuit Boards, there are 3 Resistors (might as well say 4) that burned up. 

I need to replace these and they are so badly burned I cannot see the colors on them.

They are Marked R2 and R3 on both little boards. I attached pix to this post. If anyone can 

offer any info on what value these resistors are, I would really appreciate it. Is there a 

schematic available anywhere? Thanks!!

Steve

[Today Is The Day Official]

I did some digging. I assuming because both of the resistors on each card 

do the same function, they may be all the same. 

I came up with:

R3 is a 47k Ohms 5% Resistor 

I got this from the One (R3) that is not burned up. I just don't know what the wattage is. 

If I can figure out what R2 is and the correct wattage I'll be all set. 

[pe...@submergentmusic.com]

can’t help on the value of R2, but you shouldn’t need anything higher than a 1watt rated replacement. 

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[Today Is The Day Official]

Thanks! I think I have it figured out. On this Schematic, it shows both R2 and R3 to be 47k Ohm resistors. 

Do you guys think I have this correct? The Schematic says it is for Balanced Output driver and 

it is the only schematic that contains R2 and R3. R2 and R 3 are fed on the pcb board by 18 Volts. 

On the schematic, it appears that is the same situation, but i am not sure. I know that R3 is a 47k Ohm. 

I hope that the other resistor is the same. What do you guys think? 

[Ike Zimbel]

They are 47 ohms, 1/4 watt. They are the power supply input to the IC's etc. If they smell burnt, this happened recently, if they don't, it happened a long time ago. Even when they are that burnt they may still be the correct value, so clean the leads off with some isopropyl or contact cleaner and then measure with a DMM on the lowest ohms setting. 

Resistors virtually never burn up like that by themselves, so just replacing them is unlikely to solve the problem. The most common reason for burnt ps resistors in Neotek consoles is because someone put one or more IC's in backwards (so if the resistors don't smell and they measure ok it usually means that's what happened at some point in the past, but the IC's were then put in the right way around). The 2nd most common cause is a shorted transistor. If that's the case, the resistor will just burn up again. You can test for that by measuring from the ends of each resistor to a known ground point (on the circuit card) and see if you measure a short or just a few ohms. If you do, you have a shorted component on the card. 

Ike Zimbel,

Zimbel Audio Productions

416-720-0887

www.zimbelaudio.com

Sent from my vintage iPhone

[Today Is The Day Official]

Well, I am ready to lose my mind! I soldered in the new resistors. Got it all put back together and I got still have issues. 

Both Aux A and B are passing signal. But there is something wrong. The Signal sounds like it is clipping and doesn't have that 

much gain. In my quest to this repair, I also found that the previous owner of the board had the Cue Sends wired correct 

at the back of the console and incorrect on the XLR's. I rewired the XLR's and now there is not the grounding issue it was 

having before (touching XLR Connectors produced a Hum before). 

But, now both Aux A and B send signal, but it just doesn't sound right and seems to clip or overload as use turn it up. 

Going to dig back in and see if something is out of place. Any suggestions besides tossing the Aux Master into the lake behind my house 

would be much appreciated. 

This will probably get a lot of laughs, but Anyone have a Spare Cue Section they would want to sell from Neotek Elite I? 

On Sunday, September 4, 2016 at 1:28:19 AM UTC-4, Today Is The Day Official wrote:

[Ike Zimbel]

Are you sure you put in the right resistors? They should be 47 ohms (Yellow, Violet, Black, Gold bands). You mentioned 47k a couple of times in an earlier post. If you put in resistors that are 10,000x higher in resistance, the circuit will "work" but run out of gas as soon as you push it. 

Ike Zimbel,

Zimbel Audio Productions

416-720-0887

www.zimbelaudio.com

Sent from my vintage iPhone

[Today Is The Day Official]

Ok, I think I am finally getting somewhere thanks to Ike. 

So, 2 Major Breakthroughs have happened, but not fully still there yet. 

#1 IKE, you are correct. I Put 47K Ohm 1/4 Watt Resistors instead of 47 Ohm 1/4 Watt Resistors. (So, this is definitely wrong). 

Question: I have some 47 Ohm 1/2 Watt Resistors, would it be Ok to use these? 

                I don't have any 47 Ohm 1/4 Watt Resistors. 

#2 I Tried sending signal to the Headphone Amp tonight and it was worse than yesterday. 

     Yesterday, I had sound, but it sounded like it was "clipping" (sounded bad".

     Today, when I tried sending signal again, I had Nothing, no sound and now the 2 Solo Lights on the Cue Amp Cards did not light (they did yesterday).

     Out of curiosity, I Patched Aux A and Aux B into the CUE AMP INSERT on the Patchbay and low and behold I got A+ 100% Perfect Sound. 

     

What does this mean? It won't play Sound if you don't directly patch in Aux A and Aux B. 

Would having the 47k instead of 47 Ohm resistors cause this???

On Sunday, September 4, 2016 at 1:28:19 AM UTC-4, Today Is The Day Official wrote:

[Ike Zimbel]

The 1/2 watt are ok in a pinch. 

Ike Zimbel,

Zimbel Audio Productions

416-720-0887

www.zimbelaudio.com

Sent from my vintage iPhone

[Today Is The Day Official]

Ok, now we are all good. I removed the 47k Ohm Resistors and replaced them with 47 Ohm. 

Re-Installed the module, rand some audio to the Cue, and good golly miss Molly, my headphones all worked. 

There are many good things that have come out of this. I think what caused the resistors to blow in the 1st place,

was that one the previous owners had wired up the XLR ends of the Cue Mix Outs. Last night in my troubleshooting,

its came to me to check the XLR's and make sure they are both wired right. When I opened them up, both XLR's were

in some bixxsre wiring scheme of + Positive on 1   Negative on 3-   Shield on 2. The back of the board ADC was wired 

correctly. So, I re-wired both XLR's and in fixing the Cue Mix, I re-chipped Cue 1 and Cue 2, And aux A and Aux B.Just in case 

any damage had occurred when the circuit blew the resistors.

Thank you to everyone who offered up advice and big thanks to Ike Zimbel or Zimbel Audio. Ike repairs my Power Supply 

when I 1st bought the console and it runs clean, quiet and has never given me a problem. I really appreciate your help Ike!

Steve

On Sunday, September 4, 2016 at 1:28:19 AM UTC-4, Today Is The Day Official wrote:

[Neil Thomason]

Great work Steve, well done.

Ike killing it as usual.

Neil