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IMG_0588What would be causing this kind of behavior?

I'm looking at the tach tape around the motor (this was a PS1 to PS2 conversion). It doesn't look like perfect white stripes all the way around - but rather like dark in spots, almost like wet (but it's not wet)...

As I begin to give it voltage in conventional, the motor just sort of twitches back and forth, then a little more voltage and it gets the wheels going fast - too fast. Oddly enough the chuff sound is something like one chuff and puff of smoke per 4 whole wheel rotations. That's not normal, nor even a feature in DCS mode I don't think.

Which part has gone bad? Is it the Tach tape, the tachometer reader? Perhaps a pinched wire could be causing this?

 

*Ive confirmed the problem is not in the tender / the PS2 board in there controls all my other PS2 steamers without fault. It's the engine portion which behaves the same way plugged into any good tender. The problem is at the engine, but I don't know the issue is/or where.

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Last edited by DdotCdot
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Daniel,

There is a tach tape somewhere on the forum.  John Will posted it sometime ago.  Maybe if you do a search for tach tape you can find it.  I agree with John, the most probable cause is in the tach tape or reader.  When reassembling the tach sensor make sue you have the recommended clearance.  Try this first. 

Did you say the engine speeds up erratically in conventional mode?  If that is the case, the problem could be different.

bruce

Engineer-Joe posted:
Hump Yard Mike posted:

Question for the group, why/how does a tack tape go bad?  It seems to be in fairly clean area of the engine.

thanks

Excess smoke oil can drip onto it for example. I've seen grease on them too. On the homemade paper tapes, they can lose their black color with age if exposed.

I'm pretty sure this is what happened. It feels very greasy/oily near the flywheel/tach tape and most likely the smoker was overfilled and spilled out all over it while it was in the box. It does smell like smoke oil on the tape... You can see in the pic it looks drenched. I sure hope this is all it is.

bruce benzie posted:

Daniel,

Flywheel diameters are measured in mm.  27,  27.5,  30,  31.8,  33.7

bruce

Bruce,

Thanks. The tools I have on me here are crude as I am not staying at my place this month, but it appears to be 30mm.

As you can see in the photo - the reader leads appear to be soldered in place nice and snug.

-Dan

 

IMG_0593

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While you wait for a replacement tape, if you want to experiment a bit get some correction fluid like White Out and touch up the white stripes.  I realize the tape is a bit greasy but I figure it should adhere enough and only takes maybe a minute or two.  Then run the engine and I think you'll see a dramatic difference.  The tach circuit is looking for contrast (black and white) between stripes; your photo looks more like black and gray.

 

stan2004 posted:

While you wait for a replacement tape, if you want to experiment a bit get some correction fluid like White Out and touch up the white stripes.  I realize the tape is a bit greasy but I figure it should adhere enough and only takes maybe a minute or two.  Then run the engine and I think you'll see a dramatic difference.  The tach circuit is looking for contrast (black and white) between stripes; your photo looks more like black and gray.

Brilliant. I did just that - white out over the white spots, black sharpy over the black spots and white-out boo-boos, and just like that - evidence confirmed. It was bad tape. She was running pretty darn close to normal with my quick-fix test and now I'm going to do it right, print the factory pattern and put real tach tape back on.

You guys are great, thank you so much for all of the help. Problem confirmed - Tach Tape stained by smoke oil

Problem fix = new tach tape

DdotCdot posted:

 

stan2004 posted:

While you wait for a replacement tape, if you want to experiment a bit get some correction fluid like White Out and touch up the white stripes.  I realize the tape is a bit greasy but I figure it should adhere enough and only takes maybe a minute or two.  Then run the engine and I think you'll see a dramatic difference.  The tach circuit is looking for contrast (black and white) between stripes; your photo looks more like black and gray.

Brilliant. I did just that - white out over the white spots, black sharpy over the black spots and white-out boo-boos, and just like that - evidence confirmed. It was bad tape. She was running pretty darn close to normal with my quick-fix test and now I'm going to do it right, print the factory pattern and put real tach tape back on.

You guys are great, thank you so much for all of the help. Problem confirmed - Tach Tape stained by smoke oil

Problem fix = new tach tape

And to think I was going to ship this whole engine 3000 miles across the US for a $2 fix...that would have been about 100 times that $$$. Knowledge is so valuable, so thank you all for so generously sharing. The body is so clean, I would hate to think of it having been damaged or dinged in shipping.

danke schön!

danke schön!

Last edited by DdotCdot

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