# Can't locate part: need help or further replacement

#### jeka616

Joined Jan 14, 2009
131
Good day all.

Recently I realized that voltage regulator on my bike is damaged. I took alternator apart, and found that the voltage regulator (part # DENSO 026000-7050) is damaged. It is 14V 25A regulator, T0-3 metal can.
Can't find anything suitable on the e-net. All I get is 7812, which is rated to 1.5A max.
Can anyone suggest replacement part for 14V 25 A T0-3 positive regulator ? Any brand will do.

#### mcgyvr

Joined Oct 15, 2009
5,394
Automotive/vehical topics are banned from discussion on this forum. Buy the proper Denso replacement.

#### debe

Joined Sep 21, 2010
1,294
Were not talking automotive. Its an altenator regulator, Post a picture of the Reg & altenator. Circuit diagram would help.

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#### mcgyvr

Joined Oct 15, 2009
5,394
So we can't talk modifications to the alternator/regulator of a car but modifications to a motorcycle alternator/regulator is completely acceptable??? Doesn't make any sense...

#### SgtWookie

Joined Jul 17, 2007
22,227
I found an exact OEM replacement part on a German site; it is 150 Euros:
http://www.al-electric.de/index.php?aktion=nummernsuche&nummer=DENSO 026000-7050

If you are using Google Chrome with Google Translate installed, it will do a reasonably good job of translating the text into your native language.

I see absolutely no problems in helping someone find an original replacement part to repair their vehicle to OEM specifications.

#### strantor

Joined Oct 3, 2010
5,917
Automotive/vehical topics are banned from discussion on this forum. Buy the proper Denso replacement.
Automotive topics aren't banned, automotive modifications are. Being that OP is trying to restore the vehicle to factory configuration but suggesting alternatives leaves this one in the grey area I would say. I would say we should help OP find the factory replacement, which wookie already did, so it's moot I guess.

#### jeka616

Joined Jan 14, 2009
131
wow, thanks gents for such a discussion. For sure, was not aware of any restcitions regarding the "automotive".

But to be clear, I was trying to find a chip - regulator which is in TO3 metal can, and is capable of handling 25A @14v. I keep searching on datasheetcatalog.com,
and I get only 78H12, which is rated only to 5A. But to be honest, reviewing connection wires on bike alternator, it is for sure not rated to 28A, as per manual.....so i'm guessing 5A will do charge a battery pretty good and run applications etc....

if anyone knows T0-3 packaged 14V 25A regulator, pls tell me its name.

SgtWoogie, thanks for efforts trying to locate. I can get exact part from UK, for about 40$, and I got a lot of connection which are traveling in/out my country, so they can get it for me. However, the regulator must be 5-10 bucks, and really don't need to by whole assembly. Thanks all, later... #### Jaguarjoe Joined Apr 7, 2010 767 If it's a conventional wound rotor alternator (with slip rings) you'll need to control the rotor winding (the field) in order to control the alternator output. A TO-3 linear regulator won't easily do that. The field on N-D alternators on Jeeps are controlled by the PCM, or ECU, or whatever they call it. When that internal regulator dies, you're supposed to buy a whole new PCM. However, you can substitute an external regulator from a 70's or 80's vintage MOPAR car and never skip a beat for about$2.
The last few bike regulators I've seen were all shunt regulators. Suzuki and Honda had SCR systems, Honda's were bulletproof, Suzuki's not so much. Replacing a 'zuki reg with a Honda is very common and simple.
The last few English bikes I had used the world's biggest Zener diode, right across the alternator's output. Simple.
If you still want a TO-3 25a linear reg, you'll need to use pass transistors to provide more current. Look at an LM317, its applications at the end of the datasheet has a circuit. Beware, you will ~3v headroom and a good heatsink.
If I could, I'd get a used Honda reg from ebay.

#### jeka616

Joined Jan 14, 2009
131
isn't LM317 only rated to 1.5A? 78H12 is rated to 5A, so I guess I'd use that one if get any here.

on the alternator end, there is no heatsink at all..and to be honest, I don't believe that it is able to carry 28A continuous...regardless...

I still want to locate T0-3 regulator, just don't have specs...so appreciate any specs/names.

I've looked on ebay, there are a lot of car alternator regulators, and I'm sure I can get one here in my country. Will do search tomorrow. Maybe it will be just a case of removing one from car's, and installin it to bikes.

28A still looks dodgy to me, when looking at wire size...

#### debe

Joined Sep 21, 2010
1,294
If its a slipring type Altenator then this circuit will work. Its a Bosch type copy. The transistor does need a small heatsink, the orig used the shell of the reg. Have used this circuit on altenators upto 60Amp reliably.

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#### jeka616

Joined Jan 14, 2009
131
I also located LT1038, which is 10A minimum, 14 A nominal. I think this will be good replacement?

#### jeka616

Joined Jan 14, 2009
131
If its a slipring type Altenator then this circuit will work. Its a Bosch type copy. The transistor does need a small heatsink, the orig used the shell of the reg. Have used this circuit on altenators upto 60Amp reliably.
thanks, I do have a lot of circuits to make high amp power supply. But I was looking for a "name" of linear regulator in TO-3 package, which is capable of handling >20A.

Appreciate efforts pulling this together for me.

#### SgtWookie

Joined Jul 17, 2007
22,227
You seem to be looking for an exact plug-in replacement regulator that is inexpensive.

You're not going to find one, unless you happen to find a used one at the breakers/junk yard/auto salvage yard.

I don't know whether the regulator for your bike is for regulating the fields or a shunt-type regulator, but neither of those would be listed in a typical electronics catalog; it would be rather specific for your bike.

#### jeka616

Joined Jan 14, 2009
131
Here are the pics. An item indicated red is the regulator, with part number on it. I've also attached schematics, yes it is regulating rotor as someone indicated above already.

I've managed to locate some parts, going to look tonight and potentially get em.

Will let know how the outcome is. Thanks

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#### SgtWookie

Joined Jul 17, 2007
22,227
It looks like Debe's schematic will work as a replacement for your regulator.

Make certain to use VERY good heat sinking for the TIP125, or it will overheat and burn up.

#### debe

Joined Sep 21, 2010
1,294
Other circuit i posted not suitable for this altenator. This one is its a Lucas type altenator regulator (rev engineered). This will wire straight to this altenator.

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#### debe

Joined Sep 21, 2010
1,294
A bit of an explination why it doesnt req a large heat sink. Its due to the circuit using a feed back network to make it oscilate & reduce power disipation. CRO pic of the collector of the O/P transistor. Also test setup when voltage down to 13.82V power is fed to rotor. When reaches 14.27V power is cut to rotor. Also a pic of the orig regulator.

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#### debe

Joined Sep 21, 2010
1,294
This is the orig Reg & circuit.

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#### debe

Joined Sep 21, 2010
1,294
This is the packet it came in back in 1992, \$15. Also a pic of a Bosch altenator reg from a BMW, using a TO3 type device. These are obviously custom made for Bosch/Denso. This will be why theres no info avalable for them.

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