I am building a MS-II/v3 board. I have assembled the board to the point where I am ready to do some testing. I have a Jimstim that I will be using for testing. The Jimstim has been fully tested and passes all the criteria. The first time I plugged the Jimstim to the MS-II and powered everything up with the 12VDC/1A wall wart power supply I am using, the polyfuse in the Jimstim heated up almost immediately, it got extremely hot in a matter of seconds. Given that the Jimstim tested out fine using this power supply (and still does test fine after the heating of the polyfuse), I surmised that my problem was somewhere in the MS-II.
Applying power to the MS-II directly (+12V to pin 28, Gnd to pin 19), I was able determine that D17 is getting very hot (to the same degree as the Jimstim polyfuse in the same amount of time). I have scoured the MS-II board for solder bridges and found nothing. I have cleaned the board multiple times with alcohol. As I understand it, D17 is part of the Injector 1 circuit. I have checked D18 of the Injector 2 circuit and I do not detect any heating at all. As best as I can tell no other components on the board are getting hot, though I am only applying power for a few seconds at a time.
I am pretty limited in my electronics knowledge when it comes to transistors so I am not sure how to troubleshoot this problem... there are 5 transistors in this circuit as best as I can tell. Could it be that I just have a bad diode (D17) or a bad transistor ? ...and if it is a transistor, how can I tell ? I have done some simple comparing of the voltages of the various component pins in the two injector circuits and I am not detecting any voltage differences from one circuit to the other.
I am reluctant to just proceed with replacing parts on the hope that I will get lucky and fix the problem. I am afraid of damaging the circuit board with all that soldering/desoldering.
Anyone have any ideas as a direction I should take ?
Thanks for your time...
D17 overheating
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Read the manual to see if your question is answered there before posting. Many users will not reply if the answer is already available in the manual.
If your question is about troubleshooting, configuration, or tuning, you MUST include your processor type (MS-I or MS-II) and code version in your post. If your question is about PCB assembly or modifications, you must also include the main board version number (1.01, 2.2 or 3.0).
If you have questions about MS1/Extra or MS2/Extra code configuration or tuning, please post them at www.msextra.com Such questions posted here will be moved to: a temporary MSextra sub-forum, where they will be removed after 7 days
The full forum rules are here: Forum Rules, be sure to read them all regularly.
Re: D17 overheating
Most common problems in the injector drive circuit at build time are solder bridges to the small transistors when can be difficult to see.
Dave P, London UK.
Rover V-8
MSII V3
EDIS
Tech Edge Wideband
Rover V-8
MSII V3
EDIS
Tech Edge Wideband