Need help with Ibanez SDR1000

Northamusi · 8th January 2012

Hello Folks:
Happy New Year to everyone.
I have an Ibanez SDR1000 with a problem and I am hoping someone can offer some suggestions. When I power it up, it blows two (of the four) internal fuses, almost immediately after engaging the power switch.
I am guessing that this indicates a power supply problem(?) but I don't have any experience with repairs on this unit. Does anyone have insight on where I might start?

thanks, best regards

Steve La Cerra

2N1305 · 8th January 2012

well, something's drawing alot of current. In an effects unit like this (I had to ggll it) there isn't that many things drawing lots of current. So there must be a short somewhere. Are thos fuses on the AC side or the DC side? Actually I'm just taking a guess at that... It sould be designed otherwise. Can you get a schematic?
You can start by removing ALL the regulators and verify with a multimeter, if the decoupling (filtering) caps are shorted out. Then power up the unit and look at the raw DC voltages going to those regulators. If they seem to make sense (you'll have to determine this by looking at the schematic, unless someone else here jumps in to provide info) AND the caps read OK, then it must be the regulators OR something further down the line...

It's kinda hard to tell anyone what to do not knowing their level of expertise.

how about a good picture of the innards?

Thant would help me. Or others.

Cheers,

2N

Northamusi · 9th January 2012

Thanks 2N. I'll see what I can come up with as far as photos and or/schematic.
peace
Steve

2N1305 · 9th January 2012

I looked around the web for a service manual even a scan of the schematic... could not find one. Indeed you have a tough one here.

Anyone here have the schematic?

Northamusi · 17th January 2012

Hiya 2N:
I followed your lead, so to speak. I pulled out all of the regulators and removed the power supply caps. I checked each capacitor with a capacitance meter, out of circuit (they were all OK). One by one I replaced the caps, each time powering up the unit before installing the next cap. No blown fuses.

Then I started to do the same with the regulators: I replaced them one at a time, powering up the unit before installing the next. So far no blown fuses. I am down to the last regulator, a 78M12, which appears to derive its supply from (one of) the fuses that was popping.

I'm kinda' scared to try this last old regulator(!) so before I do... can I replace it with a 7812 or does it need to be a 78M12? Is there any way to test the old 78M12?

thanks for your help! I'm close!!
peace
Steve

LeeYoo · 17th January 2012

Yes, you can replace it with a 7812. The M version just has a lower max. current.
But, those 78xx regulators are foolproof, so I would suspect problems with the circuit behind it.
If this regulator has it's own fuse, then I would put the regulator in, and replace the fuse with a (wirewound) 22ohm/5watt resistor.
If this gets hot, there is a short, but the part (e.g. IC) that is shorted will most likely get hot too.
Post the voltages before and after the regulator if you're not sure.
Leo..

2N1305 · 17th January 2012

Quote:

Originally Posted by LeeYoo

Yes, you can replace it with a 7812. The M version just has a lower max. current.
But, those 78xx regulators are foolproof, so I would suspect problems with the circuit behind it.
If this regulator has it's own fuse, then I would put the regulator in, and replace the fuse with a (wirewound) 22ohm/5watt resistor.
If this gets hot, there is a short, but the part (e.g. IC) that is shorted will most likely get hot too.
Post the voltages before and after the regulator if you're not sure.
Leo..

I think LeeYoo has covered it quite well! do what he recommended. If I recall the M versions are also isolated? Or is that only some JRC and NEC versions?

Northamusi · 17th January 2012

Hi Guys: Since I had a new 7812 on hand, I soldered it in. No blown fuses. I gave it a quick audio test and it seems to be working OK. I'm going to leave it powered for a while, and keep an eye on it. I'll let you know what happens.
Thank you both tons for your help!

peace
Steve

Northamusi · 27th January 2012

One week plus and it's still working, thanks to you guys!!
peace
Steve

Ike Zimbel · 27th January 2012

Hi Steve,
If you still have the old 7812, you can check it with a DMM and see if it is shorted between any of the two leads (just a SWAG, but I'd say the input and ground leads...). Then we would know what the issue was. Speaking of which, what was the outcome with your PCM-70?
Best,
Ike

Northamusi · 1st February 2012

Hiya Ike:
Hope all is well with you. I had already tossed the old 7812 from the SDR1000
but the unit is still functioning so it appears to be cured.

I was not able to fix the PCM70 on my own but I did get it repaired by Jim Fabiano. He did a great job.

best regards
Steve

8th January 2012	#1
Northamusi Gear Head Joined: Mar 2005 Location: Brooklyn, NY Posts: 59 Thread Starter	Need help with Ibanez SDR1000 Hello Folks: Happy New Year to everyone. I have an Ibanez SDR1000 with a problem and I am hoping someone can offer some suggestions. When I power it up, it blows two (of the four) internal fuses, almost immediately after engaging the power switch. I am guessing that this indicates a power supply problem(?) but I don't have any experience with repairs on this unit. Does anyone have insight on where I might start? thanks, best regards Steve La Cerra

8th January 2012	#2
2N1305 Lives for gear Joined: Jan 2009 Location: Canada Posts: 1,300	well, something's drawing alot of current. In an effects unit like this (I had to ggll it) there isn't that many things drawing lots of current. So there must be a short somewhere. Are thos fuses on the AC side or the DC side? Actually I'm just taking a guess at that... It sould be designed otherwise. Can you get a schematic? You can start by removing ALL the regulators and verify with a multimeter, if the decoupling (filtering) caps are shorted out. Then power up the unit and look at the raw DC voltages going to those regulators. If they seem to make sense (you'll have to determine this by looking at the schematic, unless someone else here jumps in to provide info) AND the caps read OK, then it must be the regulators OR something further down the line... It's kinda hard to tell anyone what to do not knowing their level of expertise. how about a good picture of the innards? Thant would help me. Or others. Cheers, 2N __________________ Not GerANIUM, GerMAnium, dammit!

27th January 2012	#10
Ike Zimbel Gear addict Joined: Oct 2006 Location: Toronto, Canada Posts: 454	Hi Steve, If you still have the old 7812, you can check it with a DMM and see if it is shorted between any of the two leads (just a SWAG, but I'd say the input and ground leads...). Then we would know what the issue was. Speaking of which, what was the outcome with your PCM-70? Best, Ike __________________ -- Ike Zimbel, Zimbel Audio Productions Ltd. Toronto 416-720-0887 "Studio House Calls". Authorized Warranty service for Allen & Heath, Clear-Com, Drawmer, Soundcraft, SPL and Yamaha. Repairs and upgrades to analog audio equipment including: AMEK, dbx, Neve, Neotek, MCI, Soundcraft and more. Ask about our RF frequency co-ordination services! www.zimbelaudio.com

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9th January 2012	#3
Northamusi Gear Head Joined: Mar 2005 Location: Brooklyn, NY Posts: 59 Thread Starter	Thanks 2N. I'll see what I can come up with as far as photos and or/schematic. peace Steve

17th January 2012	#5
Northamusi Gear Head Joined: Mar 2005 Location: Brooklyn, NY Posts: 59 Thread Starter	Hiya 2N: I followed your lead, so to speak. I pulled out all of the regulators and removed the power supply caps. I checked each capacitor with a capacitance meter, out of circuit (they were all OK). One by one I replaced the caps, each time powering up the unit before installing the next cap. No blown fuses. Then I started to do the same with the regulators: I replaced them one at a time, powering up the unit before installing the next. So far no blown fuses. I am down to the last regulator, a 78M12, which appears to derive its supply from (one of) the fuses that was popping. I'm kinda' scared to try this last old regulator(!) so before I do... can I replace it with a 7812 or does it need to be a 78M12? Is there any way to test the old 78M12? thanks for your help! I'm close!! peace Steve

17th January 2012	#6
LeeYoo Lives for gear Joined: Feb 2010 Location: New Zealand Posts: 754	Yes, you can replace it with a 7812. The M version just has a lower max. current. But, those 78xx regulators are foolproof, so I would suspect problems with the circuit behind it. If this regulator has it's own fuse, then I would put the regulator in, and replace the fuse with a (wirewound) 22ohm/5watt resistor. If this gets hot, there is a short, but the part (e.g. IC) that is shorted will most likely get hot too. Post the voltages before and after the regulator if you're not sure. Leo..

1st February 2012	#11
Northamusi Gear Head Joined: Mar 2005 Location: Brooklyn, NY Posts: 59 Thread Starter	Hiya Ike: Hope all is well with you. I had already tossed the old 7812 from the SDR1000 but the unit is still functioning so it appears to be cured. I was not able to fix the PCM70 on my own but I did get it repaired by Jim Fabiano. He did a great job. best regards Steve