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mitchelr
Copper Member
United Kingdom
11 Posts |
 Posted - 11/16/2007 : 13:28:05
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Hi
I have been given a damaged SD-2 to look at.
The guy said he used the wrong power supply, then gave it to a friend who replaced the diode at the power input.
Now there is no sound and the Red/Green LED shows orange all the time.
Has anyone had the same problem, or any idea's
There seems to be no schematic on the web for the SD-2, can anyone put me in touch with a copy.
Thanks
Ron |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 11/16/2007 : 14:23:50
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Hi mitchelr
Just read both the private mail that you sent me, & this topic at the same time.
I think this is what you are looking for.
Taken from the actual service manual.
http://img329.imageshack.us/img329/5053/sd2schematicrq3.jpg
Tell us more about the original fault.
Check the diode that was replaced for correct polarity & type.
Was it also the wrong voltage, as well as reversed polarity?
And how much over volts was it?
Maybe some pics.
You might want to look at the 5218 SIP op-amp,
Inject a signal into the input with a sig gen. & follow it backwards through the circuit.
Failing that use a Walkman or MP3 player as your gig gen, & loop the song so you know what audio you are listening for.
Try a 100mV 500Hz to 1KHz signal, it makes it a lot easier to trace.
You should be able to do a search for the 5218 op-amp in your fav. search engine.
Else try www.datasheet4u.com
Good luck mitchelr (Ron)
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Edited by - Dr. Bob on 11/16/2007 16:21:03 |
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mitchelr
Copper Member
United Kingdom
11 Posts |
Posted - 11/16/2007 : 16:13:46
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Excellent Thanks Dr Bob
I can get going this weekend now.
Regards
Ron
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 11/16/2007 : 16:23:03
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quote:
Originally posted by mitchelr
Excellent Thanks Dr Bob
I can get going this weekend now.
Regards
Ron
Hi mitchelr
Keep us informed of your progress.
Good Luck Dr. Bob
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mitchelr
Copper Member
United Kingdom
11 Posts |
Posted - 11/25/2007 : 12:30:14
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The continuous yellow/orange led was due to a damaged 4011, used for the switching circuits and led display.
Also three of the six 5218 op amps were also blown as well as the power input diode.
With all these replaced the unit was giging again last night, the guy was over the moon.
Thanks Dr Bob, I obviously would have had no chance without the schematic.
Regards
Ron |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 11/27/2007 : 07:41:08
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quote:
Originally posted by mitchelr
The continuous yellow/orange led was due to a damaged 4011, used for the switching circuits and led display.
Also three of the six 5218 op amps were also blown as well as the power input diode.
With all these replaced the unit was giging again last night, the guy was over the moon.
Thanks Dr Bob, I obviously would have had no chance without the schematic.
Regards
Ron
Hi mitchelr
I'm really glad you got it all going.
it must have been a very beefy & high REV. voltage plug pack, that was
plugged into it.
That's a lot of damage.
Where did you source the 5218 op amps?
Would you be kind enough to list which 3 of 6 op-amps you replaced?
And what kind of plug pack was used on it to do that much damage...
Regards Dr. Bob |
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mitchelr
Copper Member
United Kingdom
11 Posts |
Posted - 11/27/2007 : 12:12:06
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Hi Dr Bob
I got the 5218's from "littlediode_components" on UK ebay, I offered 60p each.
The three op amps damaged were 2a , 2b , 3b ( Crunch and first two stages of Lead )
Just for the record, I put a 4011AE in the switching circuit and it didn't work,I finished up putting a low profile socket in and trying different 4011's, I had a few 4011A's but none worked, I had one 4011B and that worked, is there that much difference.
I don't know what he plugged in yet, he was at a friends house practicing.
Regards
Ron |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 11/27/2007 : 14:40:52
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quote:
Originally posted by mitchelr
Hi Dr Bob
I got the 5218's from "littlediode_components" on UK ebay, I offered 60p each.
The three op amps damaged were 2a , 2b , 3b ( Crunch and first two stages of Lead )
Just for the record, I put a 4011AE in the switching circuit and it didn't work,I finished up putting a low profile socket in and trying different 4011's, I had a few 4011A's but none worked, I had one 4011B and that worked, is there that much difference.
I don't know what he plugged in yet, he was at a friends house practicing.
Regards
Ron
Hi mitchelr
The 4011A's are unbuffered IC's
Was the original a 4011B? most likely it was.
The 4011B's are buffered with protection diodes -- Hence the B suffix.
Common with all later CMOS IC's, to protect them from static voltages.
Remember to handle all CMOS & MOS IC in anti-static bags - containers or keep all the legs shorted out in tin foil, like good old lunch wrap.
You never mentioned the prefixes of the 4011's that you used.
as in CD4011A - MC140011A ?
Thanks for the info on which damaged op-amps you changed.
Regards Dr. Bob |
Edited by - Dr. Bob on 11/27/2007 14:41:52 |
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mitchelr
Copper Member
United Kingdom
11 Posts |
Posted - 11/30/2007 : 12:11:58
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Hi Dr Bob
The 4011's I tried without sucess were HBF4011AE, ( to be honest I bet they are over 25 years old ) so it might not be the chip,
The one took out of the circuit was TC4011BP
I've been building electronic projects for years, but never got into the theory
From the schematic for the sd-2 ,are the FET's just for switching or do they amplify the signal, or both
Regards
Ron |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 12/01/2007 : 10:49:53
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quote:
Originally posted by mitchelr
Hi Dr Bob
The 4011's I tried without sucess were HBF4011AE, ( to be honest I bet they are over 25 years old ) so it might not be the chip,
The one took out of the circuit was TC4011BP
I've been building electronic projects for years, but never got into the theory
From the schematic for the sd-2 ,are the FET's just for switching or do they amplify the signal, or both
Regards
Ron
Hi mitchelr
The 4011AE's are definitely UNBUFFERED, they may possibly be damaged, if hey were not handled in a static safe method.
The 4011B's are buffered.
From a quick glance the FET's seem to be only for switching the audio in for dual modes.
There is a Boss pedal that use FET's for generating the distortion, Now there is an interesting project for some of you Technically Minded menbers of the forum.
"Which Boss pedal uses FET's for generating Dirt"?
Notice I said Dirt & not Distortion or Overdrive, because that would narrow your search
Regards Dr. Bob |
Edited by - Dr. Bob on 12/01/2007 10:52:21 |
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Topic |
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SD-2 Problem
