Studiomaster 800c rebuild. |
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jbl_man
Moderator Group Joined: 12 January 2005 Location: London. Status: Offline Points: 11154 |
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Posted: 29 April 2010 at 12:30pm |
Here is an old RSD 800C i picked up dead this week,bought as broken,so i thought would post a few photos of it being rebuilt.
Cosmetic condition was quite good,considering its 32 years old,there is a a few scratches,but nothing terrible.
First step was to give it a good hoover-out,and then clean it up with fine paintbrush and air-line.
Back panel view.
It was fairly obvious that although i bought this for spares,the condition warrants fixing it,and bringing it back to life....quick visual examination revealed a handful of old corroded 20mm fuses,and several burnt resistors....
This is one of the output boards..note the burnt 5.6ohm resistor,(end of screwdriver to show)..quite big these,about an inch long,so probually 5watt? Andy tells me
there is a capacitor around 0.1 connected to it with a output coil.
Easier to see with one of the driver boards removed.
A bit awkward to see,but its hidden behind the relay on the output boards...same on both channels,so will change those.
Will post up some more photos when parts arrive.
Thanks to Andy for his help.
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Be seeing you.
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burningbush
Old Croc Joined: 25 May 2009 Location: Pictland Status: Offline Points: 5897 |
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Fascia looks very good, better than the ebay pics showed. Fair bit of minor corrosion on the solder, do you think that will cause problems? or do you think it will have negligible effect?
Just seen the pin board connection between boards, the green strip connector - looks like a sticky brick.
Love the lay out of the front panel.
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music is the message
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TRE4U2NV
Old Croc Joined: 21 May 2005 Location: home Status: Offline Points: 2592 |
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gotta luv studiomaster when fred was involved
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IM SO SECRETIVE BUT I CANT TELL YOU WHY
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Wrighty
Old Croc Joined: 17 April 2004 Location: Devon Status: Offline Points: 1801 |
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The orange/brown stuff around the solder joints is just old flux - nothing to worry about. Obviously they didn't bother with (or didn't have the equipment for) cleaning PCBs back then!
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ALL YOUR BASS ARE BELONG TO US.
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jbl_man
Moderator Group Joined: 12 January 2005 Location: London. Status: Offline Points: 11154 |
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Update time.
Broken track on one of the driver boards,had to repair a half-inch section.
New wire-wound resistors replaced old burnt ones.
Old output transistors were shorted on the right-hand channel..replaced with ten new RCA mj15003...quite awkward to get these,had to remove fan to gain access to mounting bolts.
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Be seeing you.
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madboffin
Old Croc Joined: 03 July 2009 Location: Milton Keynes Status: Offline Points: 1537 |
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You've probably done this anyway, but don't forget to check all emitter resistors for open circuits.
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Mhamplification
Young Croc Joined: 16 July 2009 Location: County Durham Status: Offline Points: 541 |
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That looks like a nice old amp there
Should be a good usable amp when you have finished it
Were these amps reliable in use I guess they must have been as the Froggy roadshow used them and I bet those took a right beasting in use
I remember repairing one back in the 1990`s the metal relays were both badly burnt so replaced them with newer plastic case ones
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phildat
Young Croc Joined: 29 January 2009 Location: manchester Status: Offline Points: 1115 |
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i have one i dont need if any one wants to make an offer...tatty case. red light doesnt light when powered up, but works fine....
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Its just a ride.
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jbl_man
Moderator Group Joined: 12 January 2005 Location: London. Status: Offline Points: 11154 |
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Ok..replaced a couple of the emittor resistors (thanks for the tip madboffin!)...and....it lives!
Appologies for the distortion on this clip,the little camera microphone just cant cope with the levels.
Edited by jbl_man - 08 May 2010 at 12:25pm |
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Be seeing you.
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burningbush
Old Croc Joined: 25 May 2009 Location: Pictland Status: Offline Points: 5897 |
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Congratulations, job well done.
What does the green light signify?
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music is the message
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Mhamplification
Young Croc Joined: 16 July 2009 Location: County Durham Status: Offline Points: 541 |
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Nice job you have done there Ian
I guess you must have sorted out the "Hi Tension" side as well !!!! Sorry couldnt resist that one
You will have to watch listen to the video to understand
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DC6ms
Registered User Joined: 14 July 2009 Status: Offline Points: 41 |
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Bless the funk!!!
Saw Hi Tension live at one of the Purley All Dayers
DC
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