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Model 1-B /SE540L driver chip [message #11098]

Sat, 30 May 2009 18:05

JayB
Messages: 8
Registered: May 2009

Junior Member

Hi, just joined the forum, you guys have a cool site here.

I've got an early seventies 1-B I'm repairing, it's definitely got a dead SE540L driver chip that was used in Kustoms of that era. I've been going bonkers trying to locate one, it seems funny that $250 minimum surplus houses claim to have hundreds and yet there's zilch availability otherwise.

Does any anyone know of a source for these 10-legged radial buggers? Or if not, a conversion mod that'll work? Any help would be appreciated.

Thanks,
JB

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Re: Model 1-B /SE540L driver chip [message #11101 is a reply to message #11098]

Mon, 01 June 2009 06:04

stevem
Messages: 4774
Registered: June 2004
Location: NY

Senior Member

What the PC board number that it is on?

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Re: Model 1-B /SE540L driver chip [message #11104 is a reply to message #11101]

Mon, 01 June 2009 12:12

JayB
Messages: 8
Registered: May 2009

Junior Member

The board # is PC5131 REV O. Never seen another Kustom that used TO-220's as power devices. I don't have a schematic but crossed the power transistors to TIP31/32's, and can pass signal through them where they connect to the SE540L so I'm pretty certain the chip is bad- it won't pass signal through it's input.

Thanks for the reply,
JB

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Re: Model 1-B /SE540L driver chip [message #11108 is a reply to message #11098]

Tue, 02 June 2009 06:20

stevem
Messages: 4774
Registered: June 2004
Location: NY

Senior Member

I have never seen a Kustom of the era that used TO-220s eitheir! Can you get a manufacture date off of any of the amps pots, it should start with 137 and then 4 other numbers?

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Re: Model 1-B /SE540L driver chip [message #11111 is a reply to message #11108]

Tue, 02 June 2009 09:59

JayB
Messages: 8
Registered: May 2009

Junior Member

The CTS pot codes are from mid 1973. The amp uses a ganged (dual) volume pot; has bass, middle and treble with a pull bright. No 'verb or trem on this sucker. There's a riveted plate on the back with serial # K-122619. I had a feeling this thing was an uncommon dog, but didn't other amps from the slant front era use the SE540L chip?

Thanks again,
JB

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Re: Model 1-B /SE540L driver chip [message #11117 is a reply to message #11111]

Tue, 02 June 2009 18:42

chicagobill
Messages: 2006
Registered: April 2003

Senior Member

I think that the I-B may be the only Kustom amp that used that driver chip. I remember repairing one maybe 20-25 years ago, dead NE540 chip.

If I dig far enough down, I may still have one of those NE540 chips around. I sent one to someone a few years ago, never heard back if he got it or if it fixed his amp.

That's one of the downsides of these forum, a lot of people come here looking for parts and answers to questions, but don't have the time or manners to let us know how things worked out or to even say thanks. But I digress, I try and look for the chip this coming weekend.

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Re: Model 1-B /SE540L driver chip [message #11118 is a reply to message #11117]

Tue, 02 June 2009 19:37

JayB
Messages: 8
Registered: May 2009

Junior Member

Hey, thanks for the reply. I figured this thing was rare rather than well done. If you do turn up an IC, name your price- it'll be more than appreciated.

Thanks again,
JB

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Re: Model 1-B /SE540L driver chip [message #11119 is a reply to message #11098]

Wed, 03 June 2009 05:56

stevem
Messages: 4774
Registered: June 2004
Location: NY

Senior Member

The NE540 does not quite have the specs of the SE40, but I guess in that circuit its not being pressed that hard.
I wish I had a schemtic of any amp that used that driver as there has to be a way to use a different op amp chip, or even two T-O5 type drivers to take the 540s place.
If you look at the circuit board, are pins 1 and 5 being used?

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Re: Model 1-B /SE540L driver chip [message #11122 is a reply to message #11119]

Wed, 03 June 2009 19:13

JayB
Messages: 8
Registered: May 2009

Junior Member

Yeah, pins 1+5, the so-called "power limit" pins of the chip are tied into the power transistors with resistors, and to what could be a feedback circuit. For the hell of it I just overpaid for a schematic from Musicparts to see if I can figure this thing out, more as an exercise than anything else- otherwise it's looking like a waste of time. The difference between the NE and SE 540L chips are in voltage rating- the NE has a max of 22 and the SE 27, this thing has 25 on it. How's that for useless arcane knowledge?

Thanks for the replies,
JB

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Re: Model 1-B /SE540L driver chip [message #11124 is a reply to message #11098]

Thu, 04 June 2009 06:02

stevem
Messages: 4774
Registered: June 2004
Location: NY

Senior Member

can you fax me a copy of that?

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Re: Model 1-B /SE540L driver chip [message #11125 is a reply to message #11124]

Thu, 04 June 2009 08:32

pleat
Messages: 1454
Registered: June 2004
Location: Belding, Mi

Senior Member

I remember I had a Kustom challenger that the Se540 chip was bad.
If it's the round silver 10 legged thing that looks like a transitor, you may have a hard time finding one.
Bob Brinkman who was with Kustom for years. Bob told me that they haven't made that IC since 1975 and he had three he was holding on to. I know the challenger ended up as an endtable. No fixing it. Bob passed away a year ago so I'm no help on finding one, just thought I'd pass on that info. Big reason why I stay away from the slant metal face amps.
Don

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Re: Model 1-B /SE540L driver chip [message #11126 is a reply to message #11098]

Thu, 04 June 2009 09:14

stevem
Messages: 4774
Registered: June 2004
Location: NY

Senior Member

the seperate head type metal face K150 250 300 and 600 do not use tha chip it seams just some combos did.

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Re: Model 1-B /SE540L driver chip [message #11128 is a reply to message #11122]

Thu, 04 June 2009 11:07

JayB
Messages: 8
Registered: May 2009

Junior Member

I don't have a fax setup right now, what I received from Musicparts was a pdf. I'd be more than happy to email you a copy, or is there a way to attach it here?

Thanks,
JB

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Re: Model 1-B /SE540L driver chip [message #11129 is a reply to message #11098]

Thu, 04 June 2009 12:03

stevem
Messages: 4774
Registered: June 2004
Location: NY

Senior Member

You can sent it to Steven.Magnotti@avispl.com.

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Re: Model 1-B /SE540L driver chip [message #11131 is a reply to message #11098]

Thu, 04 June 2009 13:30

stevem
Messages: 4774
Registered: June 2004
Location: NY

Senior Member

You know it would probibly be cheaper to get rid of most of that output stage and install something like a LM4766 output IC pack than but a SE540L chip!

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Re: Model 1-B /SE540L driver chip [message #11140 is a reply to message #11131]

Thu, 04 June 2009 19:37

JayB
Messages: 8
Registered: May 2009

Junior Member

That's actually a very good and practical idea.

Thanks,
JB

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Re: Model 1-B /SE540L driver chip [message #11141 is a reply to message #11098]

Fri, 05 June 2009 06:30

stevem
Messages: 4774
Registered: June 2004
Location: NY

Senior Member

That pack number I posted is wrong, as its stereo, bot a NTE118 pack is a mono 50 watt pack that will run off of your power supply rails 26 volts and cost less than 7 bucks!
I would also add a good amount of finded heat sink to mount it on and then bolt that to the chassie.

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Re: Model 1-B /SE540L driver chip [message #11218 is a reply to message #11140]

Mon, 15 June 2009 14:37

JayB
Messages: 8
Registered: May 2009

Junior Member

First off, thanks to everyone for their replies and suggestions, they were appreciated.

While I was about to convert the amp over to an LM3886 I came across(not that big a deal), a better, simpler solution came along. Chicago Bill dug up a C540H and sent it my way. Popped it in and the amp now works perfectly.

Thanks so much Bill, and to the rest of you guys, you were really helpful.

This is what a repair forum should be, kudos to you all.

JB

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