TI 78L09 TO-92 package the same as a JRC 78L09 T0-92?

iaresee · April 24, 2009, 10:10:27 PM

I can't seem to find a datasheet (that I don't have to pay to access) for an older JRC 78L09 voltage regulator. I've got replacements here and waiting but they're TI (see datasheet). Anything attached to mains makes me nervous so I thought I'd check in here -- does anyone know if their pin outs are the same? The board I'm repairing (an older Voodoo Labs Pedal Power) doesn't have any markings to indicate input or output. I've only got the shape of the package screened on the board.

iaresee · April 24, 2009, 11:17:12 PM

I guessed yes. But I'm waiting until tomorrow when I can pick up a fire extinguisher to test my handy work.

iaresee · April 25, 2009, 02:05:50 PM

Follow on to my question about power regulators asked here -- I replaced the 78L09s on the three outputs that were dead. Tried them out. Still dead. So either the pinouts on my regulators are the reverse of the JRCs that were in there. Or some other piece of the output chain is fried. Here's a pic of what I'm trying to fix:

Anyone ever work on one of these before? I suppose I could start replacing everything in the chain. The W005's are rectifiers. And then it looks like it's two caps per output. Any thoughts on the next obvious place to continue debugging?

aziltz · April 26, 2009, 09:19:09 AM

Quote from: iaresee on April 25, 2009, 02:05:50 PM
Follow on to my question about power regulators asked here -- I replaced the 78L09s on the three outputs that were dead. Tried them out. Still dead. So either the pinouts on my regulators are the reverse of the JRCs that were in there. Or some other piece of the output chain is fried. Here's a pic of what I'm trying to fix:

Anyone ever work on one of these before? I suppose I could start replacing everything in the chain. The W005's are rectifiers. And then it looks like it's two caps per output. Any thoughts on the next obvious place to continue debugging?

did you try to send it to voodoo lab? they have excellent repair/service.

cpnyc23 · April 26, 2009, 01:46:24 PM

My guess is that if you are using "power supply" and "don't know" in the same sentence, it might be worth spending the few extra bucks to have it worked on by somebody who does know what's going on. If you can get them to explain to you what needs to happen to fix things, just think of it as paying for the knowledge you acquire....

-chris

iaresee · April 26, 2009, 05:41:40 PM

Quote from: aziltz on April 26, 2009, 09:19:09 AM
did you try to send it to voodoo lab? they have excellent repair/service.

I haven't. But I doubt it'd be worth while. They don't make this unit any more. Haven't for a while. Besides, it's more fun to tinker. This isn't so much about making it working as the journey spent trying.

Not to mention they're not going to like the fact that I've already been in there with my iron and swapped parts.

iaresee · April 26, 2009, 05:45:40 PM

Quote from: cpnyc23 on April 26, 2009, 01:46:24 PM
My guess is that if you are using "power supply" and "don't know" in the same sentence, it might be worth spending the few extra bucks to have it worked on by somebody who does know what's going on. If you can get them to explain to you what needs to happen to fix things, just think of it as paying for the knowledge you acquire....

That's exactly what I'm looking for here: someone with some knowledge of this unit. If not here, where would I find this knowledge? There's nothing magic happening here. A/C is being split 8 ways. Rectified to DC, with some ripple filtering, and then regulated before being sent to an output. I'm just looking for some product-specific debugging help. I'm sure someone here has poked around inside one before...not magic. The end result is readily verified (if you're thinking that this could be a pedal-frying machine in the end). The A/C makes me nervous -- I don't like to work with open mains connections around. So it slows down debugging. Every time I do something I have methodically to box it all back up to test it. I got laid my finger on a big cap in a university lab where we were doing A/C work and it was a lesson I haven't forgotten.

Mark Hammer · April 26, 2009, 10:25:24 PM

This document says the JRC/NJM pinout is exactly the same as that found in every other 3-pin 100ma regulator I've seen: http://info.hobbyengineering.com/specs/NJR-ae06004.pdf

iaresee · April 26, 2009, 10:49:44 PM

Quote from: Mark Hammer on April 26, 2009, 10:25:24 PM
This document says the JRC/NJM pinout is exactly the same as that found in every other 3-pin 100ma regulator I've seen: http://info.hobbyengineering.com/specs/NJR-ae06004.pdf

Thanks Mark!

Looking at the traces on the board it's either the W005 rectifier or the A/C tap off the transformer itself for the output. I guess I have to put on my A/C probing hat after all...nuts.

iaresee · April 27, 2009, 03:52:05 PM

It's the transformer. I've got nothing at the taps for these outputs off the transformer.

I sent Voodoo Labs and email the other night and got a response today from Josh Fiden, CEO and Founder. How's that for service? He confirmed the transformer diagnoses and offered me a replacement for USD$43 + shipping.

At this point I'm going to cut my loses and just invest in a new unit I think.

But it was fun while it lasted!

Mark Hammer · April 27, 2009, 04:12:12 PM

Ah well, at least you didn't spend too much on the regulators. I'll buy 'em from you if you want. I can always use a few extras.

iaresee · April 27, 2009, 04:31:47 PM

Quote from: Mark Hammer on April 27, 2009, 04:12:12 PM
Ah well, at least you didn't spend too much on the regulators. I'll buy 'em from you if you want. I can always use a few extras.

Thanks Mark. I'm going to hang on to the extra regulators. They could be handy. Actually: as I was working on this I was wondering why we don't just build regulated power into our pedals? Other than the obvious, "Because we like to play with sagged voltages" answer -- is there any other good reason?

News:

TI 78L09 TO-92 package the same as a JRC 78L09 T0-92?