83 Heritage Special TCI troubleshooting

sleddog83

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Hi, I’ve had my bike for a few years, done lots of repairs on it. The igniter packed it in a couple of weeks ago. I spent the last couple of weeks going over it. I have traced out the board to the best of you ability. I am a retired electronics tech, so I think I have a reasonable understanding of how some of the circuitry works. I suspect the module may not be repairable, so will likely switch the bike over to a Pamco setup. Besides I have been wanting to upgrade the charger to a pma anyway. However, I plan to upload my schematic and notes on the TCI module. Hopefully it will help the next person with these problems. Will upload tomorrow.
 
Welcome to the site.........We love pics.

Pamcopete has closed up shop so no more genuine Pamcos........Might want to read this thread.
http://www.xs650.com/threads/mike-s-xs-dime-city-cycles.54826/
Yah. I saw the thread about Pamco Pete. I bought my kit through XS Direct. Just had it delivered.

I am posting my schematic for the TCI board. I don't know if I will spend anymore time on it, as I have the pamco kit here now. I may try the TCI board with the new coil, just out of curiousity. But I think the IC on my TCI board is shot.
As far as the schematic goes, I think it is reasonably accurate. The arrangement of components around the inputs and output make sense and I was able to check them. The arrangement of components around the IC is a little more sketchy. Since I have no info on the IC, can't really look at that part of the schematic and say for certain it is correct. The zeners on this board are 8.2 volts for ZD1 and 6 volts for ZD2 and ZD3. R1, R2, ZD1 and C1 make up a small on-board voltage regulator circuit for the igniter. It basically provides a stable 8.2 volt supply voltage for most of the board, rather than relying directly on a fluctuating battery voltage. The output transistors T4 and PTR use a non-regulated voltage via the R./W wire. The board appears to have four fuses on it. Well, they are labelled as resistors, but the resistance is less than 1 ohm and they are encased is a white package. My guess, given the schematic layout, is they are fuses. The IC on my TCI board is labelled as EWD101. Given that it is a Hitachi igniter module made using Hitachi components, this is likely a custom made chip from Hitachi. Good luck finding a replacement for that. I checked all the electrolytic capacitors, transistors and diodes. All were good. The only definitive fault I found was some dodgy soldering around R1 and R2 as well as some suspect soldering where the wires attach to the board. Everything was resoldered.

I started my repair using a troubleshooting guide from 650central called: If your XS650 with standard Yamaha electronic ignition has no spark. This was a very good guide except for at step 6 they suggest disconnecting the pickup coils to test them. This is crazy talk. The pickup coil impedances as well as the primary coil impedances can easily be checked from the ignitor connector. This way, you are also checking the wiring going to these components as well as the components themselves. Also the colour coding that he lists for the pickup coil impedances for the 83 is wrong. Follow the colour coding for the 80 81 models.

If anyone has any questions, ask away. Maybe this diagram will help someone else.
Ken
 

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I remember seeing that a small number of resistors or capacitors were soldered by hand, presumably because they were selected individually. That would explain R20, 21 and R22, 23. Changing the larger of the pairs would let you fine tune the resistance.
 
I remember seeing that a small number of resistors or capacitors were soldered by hand, presumably because they were selected individually. That would explain R20, 21 and R22, 23. Changing the larger of the pairs would let you fine tune the resistance.

I agree. I suspected it is an attempt to fine tune the impedance going to that section of the linear IC. Even if I could replace the IC, these tuned impedances would also have to be adjusted. These days it would all be done by a microprocessor and a million sensors. We would still be in the dark trying to figure it out.
 
I was guessing they were setting the trip point for voltage comparators in the ic. Today every component besides the micro is just interfacing for the micro. As far as I know, nobody has ever been able to find a data sheet for that ic. It would be revealing...
 
Post #13 more specifically the link and PDF file in post #14 ............i don't claim to know anything about electrics, have a lot of TCI stuff bookmarked.......
Although this is not about the actual TCI but something Mrriggs made and was selling at one stage...........
 
 

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I was guessing they were setting the trip point for voltage comparators in the ic. Today every component besides the micro is just interfacing for the micro. As far as I know, nobody has ever been able to find a data sheet for that ic. It would be revealing...

I think you would have to find the Hitachi engineer first, dig him up and re-animate him to get any info. I find it curious that there are different ICs in the different versions of the TCI boards. Mine has 20 pins, others less. There are info sheets out there for the HA1825p chips, but I don't think those chips are the same as what is being put in the TCI modules. When I first saw the info sheet, it showed a dip with less pins than the IC on my board.

Anyway, last winter I was thinking I should upgrade to a permanent magnet altenator, since the charging system is so weak on these bikes. As I started looking into it, I realized I would have to jettison my TCI ignition. At the time I thought, why replace a perfectly good ignition system. I guess I got what I wished for.
 
Sleddog83, can you put up a photo of the one it's a schematic for? I'd like to see how similar it is to the non-kickstand version I have.
On mine, D1-4 are general purpose diodes, 1N400x works. I've replaced my originals because they were fragile glass. I don't have the D7 circuit but same would work there.

Anyway, I think you should be able to repair yours at this point! First thing I would do would be quickly re-solder every connection because they're known to go bad and still look good to the naked eye. You can do it through the coating. Then I would check D1-4. Then if I had an o-scope I'd look for signal at the base of T4. I would suspect the ic last, so just may be fixable...
 
Well I think the schematic will help people who are trying to repair a repairable board. I think typically the input diodes, from the pickup coils get burned out. Those could probably be replaced with some 1n4007 diodes. I am reasonably certain of the Zener diodes, although most of the writing has been worn off the diodes, I took them off the board and tested them. They could probably be replaced with 1n47xx series diodes. I wrote down in the schematic legend what I think the voltages are. The Darlington output transistor is easily sourced from electronics suppliers as well as the other transistors on the board. Mind you, I am not certain if some of this info applies to the other versions of the TCI board. Mostly you need to re-solder the whole board, because a lot of the solder joints go bad over time due to heat, vibration and corrosion.
Ken
 
Sleddog83, can you put up a photo of the one it's a schematic for? I'd like to see how similar it is to the non-kickstand version I have.
On mine, D1-4 are general purpose diodes, 1N400x works. I've replaced my originals because they were fragile glass. I don't have the D7 circuit but same would work there.

Anyway, I think you should be able to repair yours at this point! First thing I would do would be quickly re-solder every connection because they're known to go bad and still look good to the naked eye. You can do it through the coating. Then I would check D1-4. Then if I had an o-scope I'd look for signal at the base of T4. I would suspect the ic last, so just may be fixable...
 
I have checked all of the diodes, electrolytic capacitors and transistors with my multimeter and cap meter. That being said.... electrolytic caps can still be bad even if the capacitance meter says they are in spec and the darlington transistor won't test the same as a regular transistor. All I can say about the output transistor it is that it isn't completely shorted or open, but they do test a bit differently than regular transistors. I did find some dodgy soldering that I redid,... No change. I even hooked up my oscilloscope to it. Problem is I don't have a storage scope so it is hard to capture a pulse on the scope. I re-soldered the whole board yesterday, and I will try it one more time with the replacement coil that I got with the the pamco kit. And before you ask, that was one of the first things I checked. The coil checks OK with a meter. It has the right impedances on the primary and secondary windings and no shorts. If by some miracle, the board works, I will attribute it to lucky soldering and or a bad coil that somehow tests OK. But in the end I will probably upgrade(downgrade) to the Pamco with the mechanical advance. Like I said, I have been thinking about switching to a PMA.
 
The coil for the Pamco is probably a 5 ohm primary, while the TCI coil should be 2.5 - 3 ohms or thereabouts. I think Pamco uses the points coil but I might be wrong. Things you can't test, test them by elimination, like if no output from the output transistor, look at the base and work back. Yeah, a non-storage scope is a pain if you need to catch a fast pulse. There are cheapo pc storage scopes on ebay that might be an improvement.
 
Yah. I saw the thread about Pamco Pete. I bought my kit through XS Direct. Just had it delivered.
I am posting my schematic for the TCI board. I don't know if I will spend anymore time on it, as I have the pamco kit here now. I may try the TCI board with the new coil, just out of curiousity. But I think the IC on my TCI board is shot.
As far as the schematic goes, I think it is reasonably accurate. The arrangement of components around the inputs and output make sense and I was able to check them. The arrangement of components around the IC is a little more sketchy. Since I have no info on the IC, can't really look at that part of the schematic and say for certain it is correct. The zeners on this board are 8.2 volts for ZD1 and 6 volts for ZD2 and ZD3. R1, R2, ZD1 and C1 make up a small on-board voltage regulator circuit for the igniter. It basically provides a stable 8.2 volt supply voltage for most of the board, rather than relying directly on a fluctuating battery voltage. The output transistors T4 and PTR use a non-regulated voltage via the R./W wire. The board appears to have four fuses on it. Well, they are labelled as resistors, but the resistance is less than 1 ohm and they are encased is a white package. My guess, given the schematic layout, is they are fuses. The IC on my TCI board is labelled as EWD101. Given that it is a Hitachi igniter module made using Hitachi components, this is likely a custom made chip from Hitachi. Good luck finding a replacement for that. I checked all the electrolytic capacitors, transistors and diodes. All were good. The only definitive fault I found was some dodgy soldering around R1 and R2 as well as some suspect soldering where the wires attach to the board. Everything was resoldered.
I started my repair using a troubleshooting guide from 650central called: If your XS650 with standard Yamaha electronic ignition has no spark. This was a very good guide except for at step 6 they suggest disconnecting the pickup coils to test them. This is crazy talk. The pickup coil impedances as well as the primary coil impedances can easily be checked from the ignitor connector. This way, you are also checking the wiring going to these components as well as the components themselves. Also the colour coding that he lists for the pickup coil impedances for the 83 is wrong. Follow the colour coding for the 80 81 models.
If anyone has any questions, ask away. Maybe this diagram will help someone else.
Ken

Hi Ken,
posts to this list say that Pamcos recently bought from XS Direct ain't real Pamcos but bootleg copies.
Sure they say Pamco on 'em for the same reason that an SMLE made in a cave in Afghanistan has the Woolwich Arsenal proof marks on the barrel.
Can't you find a good used XS650 ignition module some place?
 
Anyway, last winter I was thinking I should upgrade to a permanent magnet altenator, since the charging system is so weak on these bikes. As I started looking into it, I realized I would have to jettison my TCI ignition. At the time I thought, why replace a perfectly good ignition system. I guess I got what I wished for.
I see now why you aren't determined to fix the TCI. It's somewhat a matter of opinion maybe, but I think there's a consensus that there's nothing wrong with the charging systems on these bikes, and a consensus that the pma alternatives are a downgrade... There are old posts on here from people selling pmas, or selling whatever, going on about how atrocious the thing that they're replacing is. There has been a great salesman or two on here with enthusiastic followings.
 
Well I wouldn't say determined not to fix it. As a retired electronics tech I felt obligated to give it a try. In fact, I felt a personal obligation to fix it, which is why I went to the extreme of trying to map out the board. I have tried to locate a replacement module from three salvage yards. They all advised me that these modules are scarcer than hens teeth. I admit it still could be fixable. I have worked on circuit boards where resistors looked perfectly fine but are in fact open. This would mean dismantling the component by component. At one point last week I had to make a decision. Do I let the riding season drift by while poke and prod at the board, waiting for parts from sketchy suppliers in Hong Kong or do i make the jump to something else. There is no such thing as a Radio Shack or local supplier of components anymore. Welcome to the global economy( don't get me started on that rant). I tried the board again last night, this is after re-soldering the whole board. Still no luck. If I were to continue trying to repair it, I would replace the electrolytic and tantalum capacitors and darlington transistor on spec, even though there is no conclusive proof that they are bad, plus de-soldering much more of the board to check every resistor out of circuit. This would be an investment in money and time. But the problem is I can't do much about the IC. It is still a big question mark. I did look into salvaging an IC from an XJ igniter. However this would mean finding and XJ igniter first that hopefully that uses a similar IC. And as I suspect, replacing the IC might not work since it is possible that these ICs are fine-tuned with different impedances on each board. And from what I have seen among the other posts there are different ICs used on the various xs650 igniters. I weighed the options, including replacing the coil on spec, which led me to choose downgrading to a PAMCO at this point in time. I also looked into sending the module to the Netherlands to be fixed. Not really an economical choice.

As to the PMA upgrade... I have spent a bit of time working on the existing charging system. I have got it working, or more correctly, I have got the bike working adequately (with a few buts) given the limitations of the existing system. It is just inherently weak. I should have saved my notes on what I measured and observed. and my solution to get it working better. I will read up on the PMA stuff before I make that jump. I will try to reconstruct my notes on the charging solution in a different post.
 
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The coil for the Pamco is probably a 5 ohm primary, while the TCI coil should be 2.5 - 3 ohms or thereabouts. I think Pamco uses the points coil but I might be wrong. Things you can't test, test them by elimination, like if no output from the output transistor, look at the base and work back. Yeah, a non-storage scope is a pain if you need to catch a fast pulse. There are cheapo pc storage scopes on ebay that might be an improvement.
 
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