Faulty revolution reciever

P

paul delany

Registered
30 Mar 2018
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3
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Dublin Ireland
Hi folks has anyone here ever done any repairs on revo recievers I fit one the other night and smelt a bit of smoke,,the loco will drive forwards but wont drive in reverse,I'm hoping it is just a blown mosfet/ transistor?
 
PhilP

PhilP

G Scale, 7/8th's, Electronics
5 Jun 2013
25,895
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Tamworth, Staffs.
Very possibly, but take a step-back.. Why did the transistor(s) blow?

If there was something that caused the motion to lock, will it happen again??

Every loco that comes my way for work. First-thing, it get's run forwards and backwards on DC, from a bench supply which has current and voltage metering. - This way I can judge how worn the mechanism is. What current it takes (no load) and, if I wish, I can stall the loco (or try to!) and see how much current will be pulled under an extreme fault.

No amount of alternative electronics, will compensate if there is an underlying problem with the mechanism.


You may 'just' have been unlucky, with a sub-standard component? But who is to say that once under load, the loco won't draw enough current to burn out more than just an output transistor.

Sorry, but.. :wondering::think:
 
P

paul delany

Registered
30 Mar 2018
91
3
53
Dublin Ireland
Very possibly, but take a step-back.. Why did the transistor(s) blow?

If there was something that caused the motion to lock, will it happen again??

Every loco that comes my way for work. First-thing, it get's run forwards and backwards on DC, from a bench supply which has current and voltage metering. - This way I can judge how worn the mechanism is. What current it takes (no load) and, if I wish, I can stall the loco (or try to!) and see how much current will be pulled under an extreme fault.

No amount of alternative electronics, will compensate if there is an underlying problem with the mechanism.


You may 'just' have been unlucky, with a sub-standard component? But who is to say that once under load, the loco won't draw enough current to burn out more than just an output transistor.

Sorry, but.. :wondering::think:
Hello thankyou for reply I made a boo boo I applied 12v dc to the motor output terminal on the reciever to test the motors as the pickups were not good on the wheels as a test ,but obviously the circuit design did not take to kindly to seeing 12 v at the motor terminal block
 
PhilP

PhilP

G Scale, 7/8th's, Electronics
5 Jun 2013
25,895
1,466
Tamworth, Staffs.
Hello thankyou for reply I made a boo boo I applied 12v dc to the motor output terminal on the reciever to test the motors as the pickups were not good on the wheels as a test ,but obviously the circuit design did not take to kindly to seeing 12 v at the motor terminal block
Ah! Oooops! :eek::(

In which case.. Can you see a blackened / burnt-out component on the Receiver, by any chance?
It might be an output transistor, but could equally well be the transistor controlling the output??

You might only notice a slight swelling in the case, or even just a dulling of the finish to the component?
 
P

paul delany

Registered
30 Mar 2018
91
3
53
Dublin Ireland
Ah! Oooops! :eek::(

In which case.. Can you see a blackened / burnt-out component on the Receiver, by any chance?
It might be an output transistor, but could equally well be the transistor controlling the output??

You might only notice a slight swelling in the case, or even just a dulling of the finish to the component?
Yes it smells and there was a bit of smoke I will have to inquire the board and have a closer look,I dont suppose you have any used ex boards lieing around
 
PhilP

PhilP

G Scale, 7/8th's, Electronics
5 Jun 2013
25,895
1,466
Tamworth, Staffs.
I dont suppose you have any used ex boards lieing around
Not Revolution, I am afraid.. :(

The damaged component(s) could be under the heatsink? - You may not be able to spot them..
 
dunnyrail

dunnyrail

DOGS, Garden Railways, Steam Trains, Jive Dancing,
25 Oct 2009
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St.Neots Cambridgeshire UK
Sounds sadly like you have made an expensive mistake, noted the other day that the current lot are offering discounted stock.
 
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paul delany

Registered
30 Mar 2018
91
3
53
Dublin Ireland
Not Revolution, I am afraid.. :(

The damaged component(s) could be under the heatsink? - You may not be able to spot them..
Ok cheers
 
P

paul delany

Registered
30 Mar 2018
91
3
53
Dublin Ireland
HI Greg no offence taken i have since got a better picture and found the mosfet on the web yey
 
Greg Elmassian

Greg Elmassian

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8 Mar 2014
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San Diego
www.elmassian.com
Deep in the throes of getting my diesel fleets with body-mounted centerset Kadee couplers, all close coupled, and adding DCC and 2 to 4 speakers per locomotive for sound systems.

The 11 USAT F3's are done, concentrating on the USAT PA ABBA set now, as the coupler conversion pedestals are being developed... a few more switchers and then off to try to come up with a systematic solution for the slipping drivers (and resulting destruction) on the Aristo-Craft steam locos. Still about 40 decoders to install... but at least I won't run out of things to do ha ha!







Greg