Harmonicashawn Posted September 7, 2011 Share #1 Posted September 7, 2011 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 Link to comment Share on other sites More sharing options...
bkuhr Posted September 7, 2011 Share #2 Posted September 7, 2011 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. Link to comment Share on other sites More sharing options...
skydoc_17 Posted September 7, 2011 Share #3 Posted September 7, 2011 Hey Shawn, I have a good CMS From an 87'VR. If you are interested, let me know. Earl Link to comment Share on other sites More sharing options...
mbrood Posted September 7, 2011 Share #4 Posted September 7, 2011 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. Link to comment Share on other sites More sharing options...
Harmonicashawn Posted September 8, 2011 Author Share #5 Posted September 8, 2011 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. Link to comment Share on other sites More sharing options...
frankd Posted September 8, 2011 Share #6 Posted September 8, 2011 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. Link to comment Share on other sites More sharing options...
Flyinfool Posted November 7, 2011 Share #7 Posted November 7, 2011 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. Link to comment Share on other sites More sharing options...
Yamamike Posted November 8, 2011 Share #8 Posted November 8, 2011 Hey Shawn, I have a good CMS From an 87'VR. If you are interested, let me know. Earl PM'ed ya! Link to comment Share on other sites More sharing options...
bongobobny Posted November 8, 2011 Share #9 Posted November 8, 2011 Yamamike, the CMS for an '83 is different from all the rest of the 1st gens. Only a CMS from an '83 will work... Link to comment Share on other sites More sharing options...
Yamamike Posted November 8, 2011 Share #10 Posted November 8, 2011 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: Link to comment Share on other sites More sharing options...
Yamamike Posted November 9, 2011 Share #11 Posted November 9, 2011 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?? Link to comment Share on other sites More sharing options...
bkuhr Posted April 14, 2012 Share #12 Posted April 14, 2012 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. Link to comment Share on other sites More sharing options...
GeorgeS Posted April 14, 2012 Share #13 Posted April 14, 2012 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. Link to comment Share on other sites More sharing options...
Flyinfool Posted April 14, 2012 Share #14 Posted April 14, 2012 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? Link to comment Share on other sites More sharing options...
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