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Model 18 Scope Troubleshooting

huh. reading this it sounds just like my freinds model 18s issues. he wanted me to repair it and i know it would mean a lot to him. it does the thing which points to transistor failure, it shows a trace breifly on startup, i think more recently it shows nothing at all.

anyone know what the specs of the transistors would be if i wished to replace them?
 
not easy to find perfect sub

I think I do have original FET TR for 18 and 19

which one do you need ? 34-1030 or 34-1034 ?

Marantz-scope-TR.JPG
 
I am not sure, but i will take a look when i get a chance. was there two different types of boards for these? how would i tell if they were bad. If i can get the right part from you i will pay a fair price for sure. It may take me a few weeks to have the time to look into it however. How buried in the unit are they?
 
Yes board are different for 18 and 19 . The one in my picture is from Model 19 but transistors are the same .
Print the schematic in the attached picture and trouble shoot with the list of voltages that you should get on transistors . 4 are mounted on the left (unit up side down front panel close to you ) on the chassis . Be carefull and avoid short circuits with your voltmeter probe . Both of them are FET . If they are not shorted you will need to measure IDSS to see if they are fine .
 
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