Transistors?

[solarman216]

had a quick read on your link rustic, very informative, sure Briggie will make use of that, Rick

 

[Lazy-Ferret]

you should have said when you were here, I have stacks of transistors, some very old wire ended audio ones, have not looked through for BD679 but could well have one or two, Rick

Cheers
Rick, I only took it all apart today to find out which one it was..

I spent ages trying to be lazy and find a CCT Diag, before I took it out, in the hope I would be better positioned to fault find it...

Anyway, the good news is, I think I found out why it died... my Oil pipe mod must have moved a bit when I installed it, as it was pressing against the shaft of the motor making it a bit harder to turn over. Should have waited for the epoxy to have dried fully before I put the cover back on. Hopefully a Quick zap with Dremil , replace transistor, and its all sorted for another 17 years. :lol

 

[briggie]

thanks rick / rustic , im aware of the modifications in that page , my mosfet hasnt blown ( yet ) , this is a sort of insurance .

another modification not mentioned there is to substitute the fans which are 20x20x20 as standard .... for 40x40x20 thereby increasing the cfm airflow

 

[rustic]

another modification not mentioned there is to substitute the fans which are 20x20x20 as standard .... for 40x40x20 thereby increasing the cfm airflow

Before I junk computers, I always remove the small computer cooling fans for other projects as they run on 12 volts. DC.

I like to think I keep things for re-cycling...:nenau:nenau
My wife thinks I keep junk....:doh

 

[briggie]

Before I junk computers, I always remove the small computer cooling fans for other projects as they run on 12 volts. DC.

I like to think I keep things for re-cycling...:nenau:nenau
My wife thinks I keep junk....:doh

yup , same fans used in my radio ...... women just dont understand

 

[Lazy-Ferret]

logic seems to point that way.

Most high volume products tend to use components that will just manage to do the job, anyway, circuit must have been well designed, as it lasted 17 years, so the extra load could have done it.

Post again when you try the replacement transistors.

best of luck,
Rustic

Result, the new transistor arrived this morning, so I fitted it, and it all seems to be working fine..

Was quiet handy having the fire out, as it used to rattle and vibrate, not much, but when it was on at night, it could drive you slowly insane, so while it was all apart, I decided to clean it up, and see if I could cure any bits that might rattle.

The inside of the heating unit was actually very clean, just a small layer of dust. The fins, on the fan were a bit dirty, so I cleaned them, and got a few bits of stuck on lint off of them, so it should be more balanced now.

The unit sits in an aluminium housing made from bent sheet, which is obviously a universal thing, with extra knock outs for other types of fittings. Two knock outs are 4 inch holes, but they have punched them so that 3 very small bits are left in place, in theory keeping them in situ. both had broken away, so only a small bit was holding them attached, which was some of the rattle. There is an extra aluminium cowling pop riveted inside the main housing, which in turn has a small extension reflector pop riveted to that. All the rivets had worked loose over the years, so they allowed everything to vibrate, and added their own rattles as well.

The large hole for the fan passes through both cowling's, so one had the hole edges bent at 90 degrees, resulting in an edge of one aluminium sheet just touching the face of the other. I used edging trim to create a cushion.

So now it is all pop rived back together, transistor changed, and quiet as a whisper....

Result... 1 days work, and an 83p transistor.. much cheaper than the other options, and it is now better than it ever was.:clap

 

[zippy656]

Ok
will keep, looking

Will look in the stores monday too

Nope, been to the stores, nothing there

 

[rustic]

Great news,
I don't know what to say... Hope for cold weather so you can use your heater, or hope for a nice warm summer where you won't need it.:doh

We have a Propex heater, gas powered warm air heater on the boat.
Really great on those chilly late summer evenings, and Spring and Autumn breaks.

We also used it on New Years day:thumbs

Nothing worse than being cold, except of course being cold and wet..:doh

Best regards,

Rustic