Marantz 1030 - After restoration/recap, no phono signal in either channel

[zackk]

I opened a 1030 I have here.
C911 and C912 are silk screened wrong on yours.
They are right on mine.

Yes I am unlucky. I know they are in backwards from the silkscreening. The originals were in the way I had them and in that same direction coincides with the schematic and service manual board diagram.

 

[tonebells]

Not great quality but has voltage on it.



Tony

 

[zackk]

Did you confirm the pin out on you replacement transistors are correct?

Tony

Yes, and I tried reversing them (even though I already knew the answer) but figured it couldn’t hurt. Still nothing.

All my replacements transistors are ordered ECB so there’s no second guessing.

 

[zackk]

Not great quality but has voltage on it.

View attachment 1182833

Tony

Thank you!

Unfortunately, the transistors aren’t turning on. I get 35v on the collectors of all four transistors, so there is no current going through the dropping resistors before it hits the collectors from the boards power rail.

 

[zackk]

Double check orientation of H901,2 and any other C458 transistors that were replaced.
If the originals were the outhouse shape then it's the bevel face which is the front with the
print (C458 etc) being on the larger back face. The C1845's do match the ECB on the screen
but this may be another error

I missed this I’m sorry. The original 2sc1344 pair and the 2sc458 pair I replaced were all slant-faced. Is that what you mean by outhouse shaped?

I replaced them with KSC1845 according to the board’s ECB silk screening (just as I did in the tone/pre amp board, which works fine through aux). The ECB orientation on the board matches the schematic. I even tried reversing them (because at this point, why not?) and still no signal.

 

[mbz]

The original 2sc1344 pair and the 2sc458 pair I replaced were all slant-faced. Is that what you mean by outhouse shaped?

Yeah, one face has a slant/bevel, the other face is flat with the printing on it, the front face is the slant/bevel face. The printing is on the back.
This is a well known trap for C458's. I rechecked the pix and they seem ok.

 

[zackk]

So... I am a bit perplexed. I quintuple checked that the transistors were in according to schematic (which they were) and noticed that there was one spot I could trace on the unit:


Sorry it’s sideways.

The collector of the first transistor should connect directly to the base of the second transistor (making a closed loop on the schematic) and I couldn’t see that collector->base connection.

Out of ideas and in desperation, I jumped in a connection, and boom, I get signal and all my voltages are good.

Wtf?! I didn’t remove and jumpers and as far as I can tell there shouldn’t be any needed.

I ran a 400hz signal in and was worried maybe I jumped the RIAA section out or something, so I played a real turntable into it and it freaking works.... WTF?!

 

[Dingman]

Are you saying the traces on the board don't provide this connection?

 

[Steven Tate]

Reverse engineer it. What did the base of the second transistor connect to before you jumped it? Surely something.

 

[zackk]

Are you saying the traces on the board don't provide this connection?

Yes

 

[zackk]

Reverse engineer it. What did the base of the second transistor connect to before you jumped it? Surely something.

I included a picture above of where i jumped the connection that wasn’t there.
The base of the second transistor connects to that 50pf cap which then goes to the collector of the same transistor. But the connection from the previous collector to the base (the blue line I drew) wasn’t.

 

[catrafter]

Before restoration, for reference only.

 

[Steven Tate]

I have an undisturbed 1030 as my workshop listener. It sounds so good, I don’t plan on restoring it any time soon. But this is an interesting dilemma that the board traces don’t match the schematic. Par for the course for Marantz. It will be interesting to see if you find a solution.

 

[Steven Tate]

If you need any info about components. etc from one, and you can't get it from Tom's photo, I will be glad to open mine up and investigate.

 

[thxdave]

I have one, too (Ser. #4663) if you need another reference.

 

[Steven Tate]

How in the heck did this thing work originally??

 

[Steven Tate]

LOL! Apparently, when Marantz stuffed the boards, they left the component leads long enough on neighboring components, to jumper to the next connection point when they were missing the copper trace in between. When I pulled the original board apart, I didn't pay close attention to jumpered pads, so I stuffed the holes and couldn't figure out why there was no sound. C909 & 910 on early boards, had the silkscreen backwards in reference to polar alignment. (chuckling) That was the one anomaly I caught.

Wow. If I ever rebuild my 1030, I'm going to have to remember this.

 

[Jerry S.]

I just finished recapping everything, and replacing all the phono and preamp transistors on my newly acquired Marantz 1030 Tuesday, a lot of work, last night I did the bios adjustments, was able to get 18watt/ch @ 1khz and 30hz, given the math around 13RMS,

Today I tested the sound quality, preamp stage sounds much better than I expected, way better than the 2235b I bought in 1977, power amp end of the 2235b was warm sounding,

 

[Jerry S.]

I noticed that the C701 and C702 on the power amp board are both 1uf, but in the schematic it shows a .47uf on both the Marantz 1030 and 1060, did Marantz just not have that part or is the schematic wrong? I've seen 2 others on You Tube with the same stock 1uf on there Marantz 1030 and 1060's???