Marantz Model 18, in bad shape

[Sarel]

Snagged a Model 18 for about $120 equivalent, she is a bit rough. Transformer works, Scope works so there is some chance at restoring it. Early Serial # 18-2792.


No output but getting a hum on the headphones. One dial light also works. So there is that. Some lettering on the front is worn away, but that is still cool.

 

[Sarel]

Someone was here before me...


and a guest


This was on the Scope board, a wire was pinched below it, a bit sloppy... And this resistor was added, it looks like, to the back of the board, don't know if that was factory but it looks out of place.


Groetnis

 

[tonebells]

This was on the Scope board, a wire was pinched below it, a bit sloppy... And this resistor was added, it looks like, to the back of the board, don't know if that was factory but it looks out of place.
View attachment 2831336 View attachment 2831337

Groetnis

I have seen this before.

Tony

 

[Sarel]

Thanks Tony, was planning for now to leave this as is. The Scope is displaying a dot, I can adjust focus and brightness and the HV controls function as well. The Voltages checks out, well the ones I measured did. Still need to measure a few and properly check the PS section.

Groetnis

 

[Sarel]

Did a few measurements on the scope and driver board.
Scope:
12H 12.4V
12J 212V
12K/L 6.3V
12L -482V

Driver Left: Driver Right:
10F 35.9V 35.3V
10G. 36.9V 1.04V
10H.
10J. 36.2V 0.16
10K. 35.9V -1.37
10L -33V. -32V

Hmmm Groetnis

 

[Sarel]

Prompted me to look in a few more places, see what the PS delivers....
MPX Matrix:
6m 0.18V vs -36V Reg
6K -5.8V vs -12V
6L 12.4V vs 12V
6E 0.1V vs 200V

on the Scope board we do have 200V.
CR12 Zener on the -33V line is a goner. Any recommended sub for here?

Groetnis/Regards

 

[Sarel]

Also -12 V zener CR11 is gone, any sub suggestions please?

Groetnis

 

[tonebells]

Also -12 V zener CR11 is gone, any sub suggestions please?

Groetnis

Any 12 volt zener greater than 1 watt should do. I have had 1 watt not hold up in the past.

Tony

 

[Sarel]

Using 1N4752A R0 for the -33V CR12 and BZX85C12 for CR10 and CR11. That should work.

Groetnis

 

[Sarel]

Will change to 1.3W 12V, Thx Tony.

Groetnis/Regards

 

[egellings]

Snagged a Model 18 for about $120 equivalent, she is a bit rough. Transformer works, Scope works so there is some chance at restoring it. Early Serial # 18-2792.
View attachment 2831321 View attachment 2831322 View attachment 2831324 View attachment 2831325 View attachment 2831326

No output but getting a hum on the headphones. One dial light also works. So there is that. Some lettering on the front is worn away, but that is still cool.

Except for the shot 'lytics, that baby looks to be in pretty decent cosmetic shape.

 

[Sarel]

Don't know about those yet, ordered parts for the PS, will go from there. Everything needs to be imported, so long wait. Nothing available in stock locally, the joys....

Groetnis/Regards

 

[monkboughtlunch]

Don't know about those yet, ordered parts for the PS, will go from there. Everything needs to be imported, so long wait. Nothing available in stock locally, the joys....

Groetnis/Regards

Hi Groetnis,

I recommend Vishay MAL210128682E3 for the two filter caps: https://www.newark.com/vishay/mal210128682e3/electrolytic-capacitor-screw-101/dp/99W8878.

Your's looks like it's in great cosmetic condition. If that is nicotine glaze on the faceplate, it acts as a preservative and should clean off fine.

 

[tonebells]

The lettering comes off easy too!

Tony