A tale of two GG-1 's

I have 16 GG-1 locomotives and never noticed odd sizes on the Flywheels.  I MU them often but use the all mode more often than not.  I do not have an original PS 1 to look at.  I upgraded all my PS2 5 volt to three volt.  I have replaced tape and 30mm is the one I see to remember.

Thanks, Marty.  Whether I use ALL or LASHUP, the converted loco runs slower that the other.  My thinking was that Protosound didn't have speed control so flywheel diameter wasn't critical.  Continuing to think, with a tach tape on the flywheel it measures 30.02mm, if I put a 30mm tach tape over the existing tape I should be at about the right diameter - and easier than going to the lathe.  We'll see how that works tomorrow.

You can adjust the number of stripes on the flywheel for any reasonable gear ratio and/or flywheel size.  There are a number of strips for various size flywheels, the standard number of stripes is 24 black & 24 white.

Did you verify the gear ratio is the same on the two units?

If the locos were running at different speeds as you say, there certainly could be current overloads

No, John, I didn't check the gear ratio.

I'll look at that tomorrow.

Dan,

What sound file did you load into the converted GG1?

I played with a 5 volt to 3 volt conversion and a factory 3 volt with no issue.   

Dan, one crazy question.  You are talking about the scale GG-1.

This could be gear ratio if PS-1.  Turning down the Flywheel will not help.  The Slower unit, (your PS conversion) needs less tach stripes on the flywheel.  Less stripes will increase speed of loco for a given set SMPH.

Make sure both units are properly maintained though.

I would also check the factory unit against another MTH Factory engine.  If it runs faster than the other unit it can be the problem.  Dirty flywheel, misadjusted tach reader can cause it to miss count stripes and run faster than set speed.  G

I posted some information on generating tach tapes in the documentation thread pinned in this forum.  Here's the latest addition.

https://ogrforum.com/t...45#58164985231390045

Here's also a link to the previous post with an image of the MTH supplied tach tape.

https://ogrforum.com/t...85#28038234982477185

Good morning and thank you all for your help and suggestions.

Marty - sorry I was not clear at all, these are both MTH scale GG1's.  The factory PS2 unit is 20-5567-1 and the PS unit is MT5501-LP.

Barry - the upgrade kit I used was 50-1902 and the sound file is p052pp3gg1_r5s_prr050815a.

GRJ - the gear ratio on both is the same (14:1).

This morning I added another 30mm tach tape over the existing one.  This seemed to help a little since the distance between them after about 35' was only about 8".  I added my MTH factory PS2 hudson to the test and observed that (using the ALL command) both factory units ran at the same speed, slightly faster than the conversion.  When first started, at a speed of 2 or 3 the conversion GG1 is slightly faster bumping the coupler of the factory unit, so I don't think binding in the drive line is an issue.

John, thanks for the repost on how to create tach tapes, I'll do that next.

Thank you all and Happy Memorial Day.

Success.

Using a 0.078" spacing tach tape, the converted GG1 runs at the same speed as the other PS2 loco.

Thanks everyone.

Dan, well done.