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Help with Marantz Model 19 scope

PooPoo

PooPoo

Active Member
Hi would anyone know how to get my scope on the model 19 working properly. As I was adjusting the brightness from the back of the trim pot my screw driver touched some metal and I saw some spark then my scopeimage.jpg went dead so I turned it off for a moment then back on. The scope came on this time but is not working like usual. The scope just display a line and doesn't fill the whole screen like before. Does anyone know how to fix this? Here's how the scope looks now
 
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Probably fried one of the JFET's in the scope board. It should be a simple fix.

The JFET's can be replaced with 2SK30A, I would replace the pair.They are not so easy to find and some are known to be sketchy. Many available on ebay. Be sure to check the other transistors and resistors on the board while your at it. The board is a bit different but schematically the same as the 18, 19, 20 and 20B. There are many threads on repairing the scope on the 18 and 19.
 
txturbo said:
Probably fried one of the JFET's in the scope board. It should be a simple fix.

The JFET's can be replaced with 2SK30A, I would replace the pair.They are not so easy to find and some are known to be sketchy. Many available on ebay. Be sure to check the other transistors and resistors on the board while your at it. The board is a bit different but schematically the same as the 18, 19, 20 and 20B. There are many threads on repairing the scope on the 18 and 19.
Click to expand...
Oh thank you, I will order the jfets on epay from a non Chinese dealer I think a U.S. Base eBay seller Consolidated Electronics has those NOS JFETs at 12$ for a pair I've had many success ordering from them. I just don't trust the 2$ ones from China. Too Cheap is a dead give away for fakes!
 
txturbo said:
Probably fried one of the JFET's in the scope board. It should be a simple fix.

The JFET's can be replaced with 2SK30A, I would replace the pair.They are not so easy to find and some are known to be sketchy. Many available on ebay. Be sure to check the other transistors and resistors on the board while your at it. The board is a bit different but schematically the same as the 18, 19, 20 and 20B. There are many threads on repairing the scope on the 18 and 19.
Click to expand...
Is your dog a husky? Or a wolf?
 
Fet's in the scope board control horizontal and vertical positioning of the line. Can you confirm you can move the trace up and down and side to side? If you can move the line up and down and side to side it's somewhere else. If you are missing to cotton candy effect, you need to verify by inputting a stereo source into the aux such as an ipod to see if the cotton candy effect is showing up. If it does show up then the issue lies somewhere in the MPX i'd imagine- Fm side.
 
bktheking said:
Fet's in the scope board control horizontal and vertical positioning of the line. Can you confirm you can move the trace up and down and side to side? If you can move the line up and down and side to side it's somewhere else. If you are missing to cotton candy effect, you need to verify by inputting a stereo source into the aux such as an ipod to see if the cotton candy effect is showing up. If it does show up then the issue lies somewhere in the MPX i'd imagine- Fm side.
Click to expand...
I can move the trace up and down , side to side just no cotton candy even with an iPod to the aux.
 
Looking at the schematic of the 20 and 19, I believe the cotton candy effect is driven from the MPX matrix board- i'd be checking the fets on it to see if they are still in tact. I ran across an issue like this in a 4400, diode matrix board is what it was in the 4400 with a dead fet.
 
when playing on stereo mode the left channel has a little bit static when i press mono the problem goes away you guys know how to fix this problem???
 
PooPoo said:
No still trying to figure out which cotton candy transistors went out.
Click to expand...

Were you able to figure out why there wasnt a cotton candy effect on the scope? Once you turn on the scope, does the cotton candy effect work right away? Or does it need to have a string FM tuner stereo signal?
 
It needs a FM stereo signal. I replaced a transistor on the scope board and got the cotton candy back
 
Hi- I have had my Model 19 in a very good shop now 3X for repairing the scope. The transistors keep blowing. First there was no vertical movement, then when I got it back...nothing. Tech says he is having problems finding the right transistors. Question: Is the schematic correct? if not, what values should be in there? I'm looking at the schematic on HiFi Engine.
 

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