CMS Repair--any electrical engineers out there?

[Harmonicashawn]

I believe my CMS (computer monitoring system?) is damaged. Has anyone attempted a repair of the board or logic chips? I have an '89 VR and have had it for 3 years. It had a sealed battery when I got it and I know about the "resistor Mod" for the "Battery Level Warning". When I read about the Mod--I looked at my bike and saw that the probe was removed and wired into the fuse box. Mod done--right? I have recently addressed the issue of a weak charging system and shortly after solving that issue--my Battery Warning came on. I looked closer at the probe Mod and realized there was no resistor installed! I immediately installed one--then another---then a 100K "pot" in an attempt to satisfy the CMS. With the pot--I was able to try voltages as low as 2.2V with no success. I traced the rest of the circuit to the connector at the board, but all was good. I took the CMS apart looking for any obvious damage (blown caps--etc.), but all looks perfect. Despite this, I believe something within the CMS must have been damaged. I decided to unplug the red "LED" until I can fix it properly. Any help would be greatly appreciated--Shawn

[bkuhr]

Likely all you can do is repair cold solder joints simular to the thread

http://www.venturerider.org/forum/showthread.php?t=33328

 

If the actual chip was blown due to improper resistor mod, than you are probably.....blown.

[skydoc_17]

Hey Shawn,

I have a good CMS From an 87'VR. If you are interested, let me know.

Earl

[mbrood]

Yes, the chip needs the resistor inline as a current limiting device, without it, that part of the chip is history. If you burnt it out, it is no big deal to change. The chip is a TD62504P I ordered 1 from local electronic shop. There are two on the computer board The battery sensor connects to pin 1 on one of the chips. That is the one to change. another tip is to install a chip socket on the board. If you blow it again in is just a matter of prying out the chip and pressing in a new one.

[Harmonicashawn]

Thanks for the advise! All the solder joints look perfect--so I believe it is a chip /resistor/ diode (the most modern thing I've fixed is a point-to-point tube amp and some crystal microphones!). Skydoc--I will P.M. you with regards to your spare, but I may have to add your name to the title (half the parts are yours!). I would like to also pursue the chip replacement--thanks for the great advise there too.

[frankd]

You need 6-8 volts on the wire to turn off the low battery alarm. On my 83, I used a 1K ohm resistor, but on my 89 I went a bit higher, I think about 15K. If I went above that, the alarm came on.

 

Frank D.

[Flyinfool]

Yes, the chip needs the resistor inline as a current limiting device, without it, that part of the chip is history. If you burnt it out, it is no big deal to change. The chip is a TD62504P I ordered 1 from local electronic shop. There are two on the computer board The battery sensor connects to pin 1 on one of the chips. That is the one to change. another tip is to install a chip socket on the board. If you blow it again in is just a matter of prying out the chip and pressing in a new one.

 

I checked Digi-Key, Mouser, and Newark, none of them have this chip.

For those so inclined to find us a substitute IC, here is the data sheet for the TD62504P.

 

I did find the chip here thru Google but I know nothing about this company.

[Yamamike]

Hey Shawn,

I have a good CMS From an 87'VR. If you are interested, let me know.

Earl

 

PM'ed ya!

[bongobobny]

Yamamike, the CMS for an '83 is different from all the rest of the 1st gens. Only a CMS from an '83 will work...

[Yamamike]

Yamamike, the CMS for an '83 is different from all the rest of the 1st gens. Only a CMS from an '83 will work...

 

Bummer:crying:

[Yamamike]

I believe my CMS (computer monitoring system?) is damaged. Has anyone attempted a repair of the board or logic chips? I have an '89 VR and have had it for 3 years. It had a sealed battery when I got it and I know about the "resistor Mod" for the "Battery Level Warning". When I read about the Mod--I looked at my bike and saw that the probe was removed and wired into the fuse box. Mod done--right? I have recently addressed the issue of a weak charging system and shortly after solving that issue--my Battery Warning came on. I looked closer at the probe Mod and realized there was no resistor installed! I immediately installed one--then another---then a 100K "pot" in an attempt to satisfy the CMS. With the pot--I was able to try voltages as low as 2.2V with no success. I traced the rest of the circuit to the connector at the board, but all was good. I took the CMS apart looking for any obvious damage (blown caps--etc.), but all looks perfect. Despite this, I believe something within the CMS must have been damaged. I decided to unplug the red "LED" until I can fix it properly. Any help would be greatly appreciated--Shawn

 

Hey Shawn,

When you guys refer to a "pot", are you taling about a potentiometer??

[bkuhr]

I checked Digi-Key, Mouser, and Newark, none of them have this chip.

For those so inclined to find us a substitute IC, here is the data sheet for the TD62504P.

 

I did find the chip here thru Google but I know nothing about this company.

 

This appears to be another chip that would substitute- no guarantee http://www.mitsubishielectric-mesh.c.../m63803p_e.pdf

Lots available on google search, but all providers appear to be china or hong kong.

[GeorgeS]

If the unit had been operating, with 12V applied, and No resistor Installed ---

The board is most likley " fried "

 

Eaisest, and cheapest fix, is to try to find another Instrument panel from a salvage bike. Swap the boards.

 

Also, you will end up with an extra set of Speedometer, and Tach, if in future you need them.

[Flyinfool]

Just another thought.

If you have the ability to replace this chip, then you would also have the ability to add the resistor on the circuit board from pin 1 to a +12V circuit run to make it a permanent fix.

 

Hmmmmmm........

 

What if while replacing the chip you cut the circuit run that goes from the connector to pin one and add in a 6.0V Zener diode so that it will not matter if the wire is used with the probe as designed or connected to +12V. Would it really be that easy?