Part number lookup

[Granite Grinder]

Part number lookup (2H Air Control Relay)

28540-68010
This some kind of relay, wondering what it does?
Nov/86 - HJ60

 

[Chang-kuao-lo]

OpenX you'll have to look it up by vehicle.

 

[Chang-kuao-lo]

if it's for your '87 HJ60: ToyoDIY.com

 

[Granite Grinder]

I checked ToyoDIY, came up dry. I googled the part #, and found an Excel sheet listing the part, but it only shows as a relay. I can't find the same part in my other HJ, same vintage, except manual transmission. This is off an auto. Showed a price of $220.00. I'm trying to determine what it does. It is on a bracket right where the clutch pedal would be, if it had a clutch.
GG

 

[ngiri]

Air Control Relay Assy.

It is listed under the EDIC system on my fich.

hth

 

[rchalmers3]

Dude, replace that power transistor and motor on. Should cost less than the diesel you will burn going to get it at Radio Shack.

A short in the load may have drawn too much power, so buy 2 resistors in case the short condition causes another failure!!!

Look the board over closely for any further damage or loose pins. Button it up and see if it works!

Could be the driver for the solenoid operating the shut off butterfly on the intake???
Rick

 

[rockcrawler]

Dude, replace that power transistor and motor on. Should cost less than the diesel it take to go get it at Radio Shack.

A short in the load may have drawn too much power, so buy 2 resistors in case the short condition causes another failure!!!

Look the board over closely for any further damage or loose pins. Button it up and see if it works!

Could be the driver for the solenoid operating the shut off butterfly on the intake???
Rick

2x although I doubt you'll find that transistor at Radio Shack. The one that looks intact would be a 2SD571. If the two small transistors that drive the Base pins of the large ones are the same, then probably the one with the blown front will also be a 2SD571. Most likely the driver transistor for this transistor is blown also, do check as you could overload the Base pin on the 2SD571 if this is shorted. Replace the electrolytic can capacitor, don't bother testing it, with a 105 °C rated part.
2SD571 datasheet pdf datenblatt - NEC - NPN SILICON TRANSISTOR ::: ALLDATASHEET :::

 

[Granite Grinder]

Thanks guys, I'll have to start her tomorrow (if it will) to see if it will shut off. Couldn't find anything in the FSM about an Air Control Relay. This HJ also has A/C, but according to ngiri, it's listed under the EDIC, which of course the auto doesn't use. Perplexing?
GG

 

[rchalmers3]

Thanks guys, I'll have to start her tomorrow (if it will) to see if it will shut off. Couldn't find anything in the FSM about an Air Control Relay. This HJ also has A/C, but according to ngiri, it's listed under the EDIC, which of course the auto doesn't use. Perplexing?
GG

Yes, see is the motor turns off without the relay plugged in.

My guess is it's operating a small vacuum solenoid that applies vacuum to the butterfly on your air intake. This butterfly is a different version of an engine stop. Instead of cutting fuel (EDIC) it cuts air to the engine. So EDIC in this case is for air cut, instead of fuel cut.

That make any sense?

Rick

 

[rchalmers3]

Most likely the driver transistor for this transistor is blown also, do check as you could overload the Base pin on the 2SD571 if this is shorted. Replace the electrolytic can capacitor, don't bother testing it, with a 105 °C rated part.
2SD571 datasheet pdf datenblatt - NEC - NPN SILICON TRANSISTOR ::: ALLDATASHEET :::

Why replace the Cap? I seldom see failures, they are kinda off to the side electrically.

Rick

 

[Granite Grinder]

Makes perfect sense, on HJ's, manual tranny=EDIC, on auto tranny=VSV.
The VSV has been working fine to kill the engine, I stumbled upon this relay while sourcing a problem with my clock, the darn thing quit working... as well as the dash lights only for the speedo. All the rest work, looks like the speedo ones were burnt. Like others, I have been gutting excess wire from under the dash from PO. I'm not an expert at wiring, but as far as I'm concerned, there is a right way and a wrong way. At least when I'm done others will see clearly how it went together. And it will be easy to trouble shoot.
GG

 

[rockcrawler]

Why replace the Cap? I seldom see failures, they are kinda off to the side electrically.

Rick

Electrolytic caps are actually the main cause of failure in electronic equipment. When servicing electronic equipment and you replace something like a transistor, you always replace the associated caps, if you don't, the job will most likely come back to haunt you at your time/expense and you will also have an unhappy customer. A typical electrolytic capacitor has a lifespan of 2000 hours at its rated voltage/temp. To fully test an electro you need to do 2 tests, one with a capacitance meter (finds about 10% of faulty caps) and another with an ESR meter which finds the rest. If you know what you're doing you only really need the ESR meter, I hardly ever bother with the cap meter if I bother with cap testing at all. Most technicians won't even bother testing caps unless they are fault finding, they just replace the associated caps. Your time fault-finding on the bench is worth far more than replacing a few cents worth of caps.
That cap is old and only worth a few cents, so it only makes sense to me to replace it and be done with it.

 

[rchalmers3]

Electrolytic caps are actually the main cause of failure in electronic equipment. When servicing electronic equipment and you replace something like a transistor, you always replace the associated caps, if you don't, the job will most likely come back to haunt you at your time/expense and you will also have an unhappy customer. A typical electrolytic capacitor has a lifespan of 2000 hours at its rated voltage/temp. To fully test an electro you need to do 2 tests, one with a capacitance meter (finds about 10% of faulty caps) and another with an ESR meter which finds the rest. If you know what you're doing you only really need the ESR meter, I hardly ever bother with the cap meter if I bother with cap testing at all. Most technicians won't even bother testing caps unless they are fault finding, they just replace the associated caps. Your time fault-finding on the bench is worth far more than replacing a few cents worth of caps.
That cap is old and only worth a few cents, so it only makes sense to me to replace it and be done with it.

rockcrawler, I think I can learn something here.

I understood Capacitors function as current storage/buffers in an electronic circuit. (think of a pulsation dampener in hydraulics) Are Electrolytic caps somehow different than other caps, or is my understanding of the use of capacitors incorrect?

Please walk me through the various failures of Electrolytic caps and point out how they can pop a driver.

When looking for the cause of the driver failure, my experience would have me looking first for a short in the load circuit, causing too much current flow through the driver.

Your posts indicate you look at the line current operations. I'm curious as to your reasons for this difference as well. Or maybe you also find a shorted load causes popped drivers AND other line damage, like caps and resistors???

To the OP:

I have a known good working VSV for measuring the ohm value of the coil if needed.

Cheers to all,

Rick

 

[rockcrawler]

rockcrawler, I think I can learn something here.

I understood Capacitors function as current storage/buffers in an electronic circuit. (think of a pulsation dampener in hydraulics) Are Electrolytic caps somehow different than other caps, or is my understanding of the use of capacitors incorrect?

Your concept on capacitors is correct Rick, however the problem with electrolytic caps is one of construction not function.

Take a 0.1uF ceramic/monolithic bypass capacitor on the power pin (VDD) of say a 555 timer chip. One side of it is tied to the chip's VDD pin and the other to ground. It does two things; 1.) provides a current storage buffer for small power fluctuations and 2.) an almost zero inductive path to ground for any stray AC. In both ways you can see it acts as a filter.

In say a power supply circuit, the electrolytic filter caps are located after the AC rectifier and remove rectification ripple (small low frequency bumps over time on the DC) and provide the the circuit the P/S is supplying power to with a cache of ripple free current.

Lots of other ways caps are used of course, thats just a couple.

Please walk me through the various failures of Electrolytic caps and point out how they can pop a driver.

An electrolytic cap is made up of two strips of (usually) aluminum foil sandwiched between some paper and rolled up and put into a can. This is filled with a liquid called electrolyte which provides the electrical isolation medium between the aluminum plates. The can is then sealed with a rubber stopper through which the leads pass through. The problem with this is that the electrolyte dries up over time causing the cap to start acting like an AC resistor (thus you need an ESR meter to measure this AC resistance). As the electrolyte dries it produces gas causing the rubber seal to start leaking electrolyte. All this is compounded by the resistance producing internal heat perpetuating the problem. As circuits are finely tuned machinery, this can cause voltages and currents to rise above the specs of the parts causing failure, or in the least, cause incorrect operation. For instance, with CRT based equipment (monitors, TV's) the switching power supplies are basically current pumps, depending on demand the current storage caps are charged faster or slower. The reason for this setup is energy efficiency. Given that that there are electrolytic caps on the oscillator of the pump and that as these dry the frequency of the pump increases, the whole working voltage of the circuit keeps increasing until it fails. Most equipment these days use switching power supplies and the root problem is usually electrolytic caps.
An electrolytic cap will at one point short as it dries out, though usually it will cause major problems before that happens.

Electrolytic caps have a positive and negative terminal. This can give the impression that there is something special with them as compared to other non-polarized caps. There isn't. This is just a by-product of its production, nothing else. It is just cheaper to produce polarized electrolytic caps than it is to produce non-polarized electrolytics.

When looking for the cause of the driver failure, my experience would have me looking first for a short in the load circuit, causing too much current flow through the driver.

Absolutely, especially in this case.
Don't forget though, a shorted cap or other component can cause the same symptom if its connected at that point.

Your posts indicate you look at the line current operations. I'm curious as to your reasons for this difference as well. Or maybe you also find a shorted load causes popped drivers AND other line damage, like caps and resistors???
Rick

I'd say most problems with electronic circuits, especially ones that generate some sort of power and heat, is caused by the circuit itself, but I would certainly look at the state of the load before anything else. If the problem is not complete failure, I normally isolate the problem area by disconnecting it from the load or next system unless the cause is obvious.

Having replaced more electrolytic caps by far than anything else, and having seen them cause most problems in things that I have had to repair, I guess it has made me cynical to the point that my first cursory glance at a broken down piece of equipment is at them.

edit: by the way Rick, my original post on this was in addition to your recommendations, all the things you mentioned must of course be checked also. I should have made this clearer.

 

[Granite Grinder]

Here's the update: This will be good knowledge for those who believe that just because a diesel is turning over it should start. I could not start the 2H without this relay plugged in, obviously it controls the VSV. Without this inline the VSV keeps the butterfly closed, so no start. Plugged her back in and all was well. I didn't unplug the relay with the engine running for fear of a ground arc/fault, but I'm pretty certain that the motor would stop. This relay is still functioning even though one of the transistors is blown apart. Could that transistor still be working? Does the board have onboard redundancy? Thanks for the info rockcrawler, I'll be swapping out the cap as well. Just to be clear, it's probably in my best interest to change out both transistors and the cap, maybe also check to see if a resistor failed as well, does this sound solid?
GG

Edit: I believe the reason for this minor explosion was some wiring from the PO. He had tapped into a wire going to the relay and was using it for????
I think it might have been for a trigger on another relay he installed, maybe to allow the stereo to turn on/off with the key. I hate it when people just grab wires randomly to use for this purpose... ARG!

 

[rchalmers3]

Good detective work and good news, GG. Sounds like you have a solution at hand.

I'd definitely take that power tap on the relay wiring to a proper fused location at the fuse block or other proper power tap!

Question: If the relay worked (due to redundancy) why did you remove it and pop it open?

Rick

 

[rchalmers3]

.....this can cause voltages and currents to rise above the specs of the parts causing failure, or in the least, cause incorrect operation.

Current rise, gotcha.

Don't forget though, a shorted cap or other component can cause the same symptom if its connected at that point.

I'm not clear on this point. If the cap is before the driver, then the cap will make smoke and open the circuit. If its after the driver, it will allow higher current flow through the driver and the driver goes bluey, correct?

I'd say most problems with electronic circuits, especially ones that generate some sort of power and heat, is caused by the circuit itself, but I would certainly look at the state of the load before anything else. If the problem is not complete failure, I normally isolate the problem area by disconnecting it from the load or next system unless the cause is obvious.

Divide and conquer, gotcha!

edit: by the way Rick, my original post on this was in addition to your recommendations, all the things you mentioned must of course be checked also. I should have made this clearer.

No worries, mate, I appreciate your apparent experience and thoughtful posts. As a former professional, there was a lot of pressure to make rapid and effective repairs. Shop/business practices prevented us from opening electronic assemblies to see what could be done to repair them. As a result I didn't get too many opportunities to delve into electronics, and I appreciate someone like you who apparently has. Cheers,

Rick

 

[Granite Grinder]

It was rattling Figured something that looks electronic and is rattling can't be good. The rattle was the piece that blew off. The only reason I even moved this relay was to get a better angle to tape up the wires after I removed the tap.
BTW: I fixed the clock, turns out the lighter plug and the clock plug are the same, just different colours. Go figure
GG

 

[rockcrawler]

I'm not clear on this point. If the cap is before the driver, then the cap will make smoke and open the circuit. If its after the driver, it will allow higher current flow through the driver and the driver goes bluey, correct?

Yes, although you are concentrating too much on what's after the drivers. In this case with this simple circuit it would not surprise me if it was caused by the load, then again that transistor could have shorted all on its own from old age too, it does happen. Most faults with electronic stuff is caused by the power supply section which apart from the output section of the circuit is the hardest and hottest working bit. Take an audio amp, they quite regularly blow output transistors even though the load (speakers) is ok. Radios - load is an antenna, they blow output transistors too even though the load remains unchanged.

No worries, mate, I appreciate your apparent experience and thoughtful posts. As a former professional, there was a lot of pressure to make rapid and effective repairs. Shop/business practices prevented us from opening electronic assemblies to see what could be done to repair them. As a result I didn't get too many opportunities to delve into electronics, and I appreciate someone like you who apparently has.

Yes, if you are going to make money out of a business, or if you are employed by someone to carry out work, in either way you will have to home in on the problems rather quickly or you will be out of work. I realize that with the internet there has been an apparent rise of IQ and a whole heap of "experts" have come out of the woodwork. However I think it would be a mistake to think there aren't any people around that do know something about the field they claim to be knowledgeable in

This is a pic of my bench, I do my design work on this and board level repairs. I have another desk in a corner of the garage where I take care of the bigger and dirtier stuff and a shelf full of other test gear that I do not use on a daily basis. Last design I did on contract was the computer/logic board for a vehicle electrical system test jig to be used on a vehicle production line. I got this contract from Bosch who in turn got it from General Motors Holden.

 

[rockcrawler]

Here's the update: This will be good knowledge for those who believe that just because a diesel is turning over it should start. I could not start the 2H without this relay plugged in, obviously it controls the VSV. Without this inline the VSV keeps the butterfly closed, so no start. Plugged her back in and all was well. I didn't unplug the relay with the engine running for fear of a ground arc/fault, but I'm pretty certain that the motor would stop. This relay is still functioning even though one of the transistors is blown apart. Could that transistor still be working? Does the board have onboard redundancy? Thanks for the info rockcrawler, I'll be swapping out the cap as well. Just to be clear, it's probably in my best interest to change out both transistors and the cap, maybe also check to see if a resistor failed as well, does this sound solid?
GG

Edit: I believe the reason for this minor explosion was some wiring from the PO. He had tapped into a wire going to the relay and was using it for????
I think it might have been for a trigger on another relay he installed, maybe to allow the stereo to turn on/off with the key. I hate it when people just grab wires randomly to use for this purpose... ARG!

That transistor is definitely gone.
If you're unsure about the state of the small transistor that connects to the big blown one change it.
Yep check resistors.
Also check those diodes too.
Piss that cap off.

edit: I know nothing about that board other than what I can see from the pic. Redundancy isn't something that's built into automotive stuff, even overengineering for reliability is a dirty word in that field. Most likely there's two switches/relays on the board and they control two separate things.
That extra wire to the relay would only effect your board if he tapped into on the relay's coil side, bit silly if he did that and tried to run an extra relay from there.

A box of blown parts and a transistor showing catastrophic damage similar to yours.