Ross systems pm 6130 schematics

[BarFly44]

Hello; any schematics or parts layouts for this mixer / amp ?

Opens mains fuse when powered on, I isolated it to the power amp pcb but most the part numbers are obsolete trying to x-ref into nte, any help would be of much appreciation..

Thanks in Advance..

[Jazz P Bass]

Can you post the transistor part numbers?
NTE parts are not always equivalent.

[BarFly44]

re; ross 6130

Thanks, the ac reg is an asahi us602, the rectifier diodes are a bzv40c12, the pcb uses two of them/one for each channel, One diode was found to be out of limits, not the usual .4 to .6 with the meter on diode function.. replaced w/1n5820 and nothing, opens main fuse, the mains/120 vac runs straight into this us602, diode/continuity function show this part/vreg to be "open"..

The bcv rectifier diodes dont cross over in nte but have found this part at obsolete electronics supply in california.. is there a substitute part number for these ?

[J M Fahey]

Please do not "shotgun" meaning replacing parts at random hoping to fix it.
You'll be chasing your tail.
If you burn fuses very probably the power transistors are shorted, plus any parts they took with them.
That us602 part is a thermal switch, the BZV40 is an European Zener diode.
You replaced it with a Schottky diode.
Post a couple clean sharp pictures; but please consider this repair might be a little over your head.

[BarFly44]

re re; ross 6130

So, the bad choice in the chosen schottky barrier diode sent to much pfv or piv dc to the op amps or even ac to them and cooked them ?

And continuity through the us602 thermal c/o trans. means it is good ?

Are the euro zener' of a special type ? i.e. peak volts and or amps ? 5 watt case ?

Amp pcb is in mixer chassis.. I will pull it, again and post some pics..

thx,

[Jazz P Bass]

BZV40C12
General Purpose Reference Regulator Diode
Various
Regulators,Diodes
V(Z) Nom.(V) Reference Voltage=12
@I(Z) (A) (Test Condition)=100m
Tolerance (%)=5
Z(z) Max. (Ohms) Dyn. Imped.=2.5
P(D) Max.(W) Power Dissipation=5.0
Package=Axial-9
Military=N

Zener diode 12 Volt 5 Watt

[J M Fahey]

*Maybe* you didn't fry your preamp ; I have (more than once ) forgotten them and slammed poor TL072 with up to +/-25V instead of +/- 15V and never burnt one ...
Anyway their being just one on each power board makes me think they are part of the input differential pair biasing, probably you killed nothing, although I wonder at the 5W rating.
Post those pictures, both sides, including some *before* pulling them from the chassis.
In fact I would unscrew them but leave them connected, fastest troubleshooting is "dynamic", trying to make them work, and not "static" (measuring parts, unpowered, trying to find something out of range).
Search for lamp bulb current limiter around here and build one.
*Always* plug the suspect amp there, until fairly certain that it has been repaired.
Also test the boards with no speaker connected.
Good luck.

[BarFly44]

re re re; ross 6130 pm

Jazz P and H M thanks much,

The lamp limiter is a good idea, it shouldnt' be a problem with a 1500.00 pinball parts inventory on hand ... lol

And the static vs. dynamic thing is also a good direction to try and diagnose; will any 5 watt/12 volt zener/switching diode work in place of the bcz40 ?

Also, no speaker load during tests might help isolation of the problem..

[J M Fahey]

Yes, 5W 12V spells it.
Post the codes written on any transistor and don't forget those pictures.
>>>>>>>>>>> Look what I've found ! >>>>>>>>>>>>>>>>>>>>
These guys have the 12 page user manual, with fold-out schematics, for $5 + postage.
Ross (Ross Systems) High Quality Service Manuals User Owner Instruction Manuals Schematics Brochures Literature Printed PDF (some FREE)
They refer to the PC-6130 , not PN-6130, but it must be either a typo or practically the same model.
The power amp must be certainly the same, since it's also used on their PC-4100.
Often manufacturers use the same power amp with different preamps.
I'd ask one copy if I were you, specially considering the low cost.
The code price G3 is in:
StereoManuals Manuals G (General) Price and Shipping Codes Chart
They say that the "main" (mixer) schematic has some unreadable values but the Power Amp is OK.
EDIT: check these guys too:
http://www.gourmetpa.com/r.html