Hi all - I have a 1990 mercury/mariner 60hp and have had a cdi failure on the system. I have removed all the epoxy and exposed the entire board.
There were 6 transistors soldered in that i removed. Only one came out in good enough shape to get a reading. My friend plugged it into a transistor reader on his multi-meter and it registered on the npn type and showed 1500 on the reading scale.
Attached is a pic of the board, I also noted down which leg went where on the circuit board (to assist with gate / etc pinouts).
Since mercury have fun not printing any part numbers on their equipment I thought id give it a go and try get similar spec transistors in there..
I know the DC volt readings into the cdi (from the trigger) is in the 3.8-5.2v (as read on my dva adapter), so i think it may be quite easy to try replacing these and having a try - would any 5v transistors work?
I dont care if the thing goes poof, its lying in my garage waiting for some input.. if i can get this cdi working again ill be incredibly happy as I blew a 2nd one by mistake and they are burning a hole in my pocket!
Basically what happens is the stator charges the capacitor in the cdi, and then the trigger signals these transistors to "release" the volts from the capacitor to the coils primary side. The voltage on these (idling) is around 120v-140v.
Ill try make a better pic of the bottom / top showing where the ground is - ill have to go back to my notes.. are all npn transistors the same pinouts? Could I test them with a diode test to find the pins?
many thanks!
Also - on the one pic ull see a big grey thing connecting the main ground.. i broke one while removing epoxy - what could this be? there is one for each cylinder/track (3 total). Or should I de solder a good one and get specs from that? Would it be a resistor? The cap is a 250v one -
There were 6 transistors soldered in that i removed. Only one came out in good enough shape to get a reading. My friend plugged it into a transistor reader on his multi-meter and it registered on the npn type and showed 1500 on the reading scale.
Attached is a pic of the board, I also noted down which leg went where on the circuit board (to assist with gate / etc pinouts).
Since mercury have fun not printing any part numbers on their equipment I thought id give it a go and try get similar spec transistors in there..
I know the DC volt readings into the cdi (from the trigger) is in the 3.8-5.2v (as read on my dva adapter), so i think it may be quite easy to try replacing these and having a try - would any 5v transistors work?
I dont care if the thing goes poof, its lying in my garage waiting for some input.. if i can get this cdi working again ill be incredibly happy as I blew a 2nd one by mistake and they are burning a hole in my pocket!
Basically what happens is the stator charges the capacitor in the cdi, and then the trigger signals these transistors to "release" the volts from the capacitor to the coils primary side. The voltage on these (idling) is around 120v-140v.
Ill try make a better pic of the bottom / top showing where the ground is - ill have to go back to my notes.. are all npn transistors the same pinouts? Could I test them with a diode test to find the pins?
many thanks!
Also - on the one pic ull see a big grey thing connecting the main ground.. i broke one while removing epoxy - what could this be? there is one for each cylinder/track (3 total). Or should I de solder a good one and get specs from that? Would it be a resistor? The cap is a 250v one -
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