Phonoland

Stupid question...I need to replace a resistor on a 311134 board in my DCC-2 as it seems to have burnt (prior to me getting this unit). I have the ohm and tolerance specs which are 4.7kohm 10% (Yellow, Violet. Red, Silver bands) but what is an appropriate Watt for these 1/2w, 1/4w or 1w?

Thank you for any advice.

Resistors, like fuses, open up, overheat, or "burn" usually for a reason.
Merely replacing one without determining the reason why, is as bad as replacing a blown fuse.
It just pumps more voltage/current into a circuit that may have other issues.
Depending on where and what the resistor's function is in the circuit also determines its rating.
The simple formula of P=IxE resolves the rating question.

Well I have been doing alot of cabinet and restoration on another unit so have not looked at this until now.

So here is the situation and maybe someone can give me a direction to go in. I have the schematics for the DCC-2 for the USC-2. On the Buffer board resistor R3124 (1K) is frying the minute the mech is engaged. That resistor is pathed to pin 20 & 19 on the buffer circuit. Pin 20 is connect to -27 VDC and 19 Data "A" Receiver Input which is Pin 4 (blue connector). Also resistor R3120 (4.7k) fried as well which is part of the same Data A Buffer structure as the other resistor.

Where would be a good starting point to try and troubleshoot/track down what is causing this short?

Ron,
That's absolute crazy-ness-- Of the thousands of the /DCC's I have repaired, I have never see anything "fried" on the buffer board--a bad transistor/diode, or a cracked resistor, once in awhile--and quite a few where the transistor leads were twisted together--sorry, no ideas here--The motor circuit is not supposed to be anywhere near this circuit ?? Ron Rich

Sounds maybe like it was "putzed with" by one of those internet wannabe technicians.
Oh well.

The only thing that I have done is recap the power board (311125) but the 2 resistors fried prior to me recapping anything. The USC-2 I bought did not have a DCC so the guy I bought it from gave me (no charge) this DCC-2. So not to unhappy since I got it for free. I picked up a new buffer board but uncertain if I should chance it as I dont want to fry another one, granted I have a ton of resistors to replace anything that might be wrong.

I will keep checking, it has to be something stupid

Ron,
I THINK it's a pinched wire harness, somewhere allowing hi voltage to cross into that circuit ? Check internal cabling in the USC---Ron Rich

Well after going through the entire harness last night looking for a short, I came up empty. So I took a change and replaced the 311134 board with one of the 2 new ones I picked up (have a spare incase), No Short. I do not have an Amp in the USC-2 yet but moving the mech and making selections and manually engaging Play on the mech burnt out the resistors on the other board immediately, so far no issue.

The difference is the original board was a 311134-1 the new one is a 311134-2, new rev of course. The old board does look like the backing peel away from 1 capacitor and 1 resistor (not one that fried). So for NOW I am taking this issue as a back board but will continue to investigate to make sure there is not an issue that might be intermittent.

Ron,
I almost need to assume there was some intermingling of the voltages to the 5 cent coin switch--maybe someone installed some type of "free play button" ?
As for the differences between the -1, and -2 boards, I cover that in the Seeburg Trouble Shooting Guide---
Ron Rich