Marantz 1060 Dead Phono Board

kevinrontel

New Member
In the midst of re-building a Marantz 1060 (new caps, trannys, whatever else is required), my phono input went dead.

Context: The phono board had been passing signal on one channel; new electrolytics, transistors, and output caps brought me up to two channels, but I'd goofed up and installed wrong-sized output caps, which filtered out most of the audible signal. Upon replacing the caps: nothing.Using an audio probe, I've established the signal goes kaput on both channels right around H901/902.

I suspect it's a power-supply issue, but I've been unable to sort out what's going on in the selector switch with its various settings.

Question: Can one of you kind folks lemme know if the following DC voltage readings are where they should be?

With selector switch in PHONO position:

J912 = 1
J914 = 36.3
J916 = 1

J913 = 1
J915 = 36.1
J917 = 1

J 904 = 41.5

Selector switch in MIC position

J912 = 7
J914 = 7
J916 = 29.7

J913 = 7.1
J915 = 7.1
J917 = 30.8

J 904 = 41

Much obliged!
 
Do you have the service manual?

I think you are on the right track - ie: first asses if power is getting to the phono section. Find the + and - pins or connections on that board and probe there for starters
 
It's a pretty simple board. Power, LR Input and output. You said you replaced the transistors. Ive rebuilt two of these, and in one I put one of the new transistors in wrong forgetting that the replacement had a different pinout from the original. It was in backwards.
 
Thanks for all the replies. I'm gonna respond to everybody (so far) in one post:

Look over your work for solder bridges and iffy solder connections or lifted traces. Check cap polarities.

What are the caps identifier numbers Cxxx ?

Prior to posting here, I had re-flowed solder, checked for splatter shorts, and repaired lifted traces. (The traces on this particular board seem very enthusiastic about coming loose.)

The caps are C917 and C918.

Do you have the service manual?

Yep, I have the service manual from hifi engine. Nevertheless, I haven't been able to ascertain what voltages should be going into the phono board, and therefore I'm unable to confirm if the board's getting proper power.

Pre-out/main-in jumpers still in place?

Yep, the jumpers are in place.

It's a pretty simple board. Power, LR Input and output. You said you replaced the transistors. Ive rebuilt two of these, and in one I put one of the new transistors in wrong forgetting that the replacement had a different pinout from the original. It was in backwards.

The transistors are all correctly oriented.

Other than my snafu with the wrong caps (I mis-read ".47" as "47") in C917/918, the board seemed to be working after I'd replaced the transistors and caps.

I'm sure I goofed something up when I fixed the cap snafu. I dunno what I could have done that would kill both channels, other than screwing up the power to the board. The fact that the signal appears to disappear at the first transistors in the circuit would supports that theory. Alas, I'm not sure what the voltage readings should be.
 
C919 IS marked wrong on the phono board. Here is a new cap in the CORRECT way, with the '+' clearly marked wrong on the board.

View attachment 1335271

I can confirm that C919 is correctly oriented (in spite of the wonky board)

R931 checks out at 100 ohms

The collectors on each of the six transistors (H901-H906) show ~40V, which suggests that power is NOT the problem.

I'll re-re-re-check all the caps (especially the coupling caps) in the audio portion of the circuit.
 
Bear in mind, the collector is the middle leg of KSC1815 and KSC1845 replacements. Still leaves room for the emitter and base to be reversed.

I should confirm that I've got the correct replacement transistors in here:

H901-904 = originally 2sc1000
H905,906 = originally 2SC458

All six replaced with KSC1845, as recommended here: http://www.vintageaudiobliss.com/2014/01/marantz-1060-console-stereo-amplifier.html

It appears that the replacements have the same pin-outs as the originals.

Do I have this right?

Possibly unrelated: I just checked for DC on the speaker outs. The left + shows 22VDC and the right + shows 1.1VDC. Neither of those seems appropriate.
 
Screenshot_20181120-160038_Samsung Internet.jpg

I think the 1000 is backwards, E-C-B, whereas the 2SC458 is B-C-E. Might be your problem. The replacements are B-C-E.
 
Oops.....

Might have THAT backwards.....
See this.......

View attachment 1335636
Depends on what the original 2SC458 transistors look like. There are two case styles for this TO-92 transistor.If they looked like little "outhouses" 2SC458 pin-out can be confusing. If they look like the new KSC's the pin-out is the same.



33076963846_ed86705598_o.jpg


https://www.datasheetarchive.com/pd...2c171b9d1226ef4d3a7cc9bf87&type=M&term=2SC458
 
Last edited:
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