[iruossim]

Has anyone ever worked on these? Or at least have a manual that tells me how to check that this is my problem.

My 420 was out stretching its legs after about a month off since the last snow. I had just shut it off to attach the 48 Tiller. When I went back to start it... nothing. Its got lights on the dash, however very faint. On, Off, On, Off with the key switch about 5-10 times and then the lights come back full glow. Won't start either way... When I click over the key switch I can hear the click of a breaker, I finally located it as being in the TDC box by feel.

I checked the voltage at the battery and before and after the fuse block, 12.5+ volts.

Earlier this winter my PTO clutch on the front melted down. Could this also be what caused that to fail? I'm not ready to throw $220 at a new TDC module. Specially after spending $300 for a new PTO and $115 for filters, oil and a new belt.

 

[andrewn]

I have a good used TDCM in good working condition for $50 if you end up needing one and want to save a few bucks.

 

[ddogg]

Matthew, I just got out of surgery and my head is killing me - probably shouldn't be posting, so apologies if I sound cranky.

Why is it the first thing a person thinks of is which parts to replace?

Here's what I would do.

Load test the battery (no, measuring voltage with your meter is not adequate).

Clean, inspect, and tighten all your electrical connections. And by all, I mean ALL OF THEM. Not a couple, not just the battery cables, but all of them, including that little satan worshiping ground lug under the battery tray which comes from the TDC.

But to your question, yes, there was a recent thread on testing a TDC. That is not your problem though.

$50 spent on the service manual is the best use of your money if you are wanting to buy something, btw.

 

[iruossim]

Small update... I relocated the battery and removed the plate it sits on to access the TDC box, I opened it up and blew out a few dust bunnies. Not much in there to speak of. Anyway while I had it open I tried the key switch again, no issue this time. Started right up, didn't give me any issues. I'm not really sure what the issue was or is...

I went ahead and replaced all the fluids and filters as I had them in the box waiting to be put in/on.

Anyway, what do you guys think the issue was?

 

[twocyl001]

I think you should clean and dielectric grease every electrical connector even remotely close to what you moved. Unless you find a connector obviously corroded, you may never know which one was causing the problem.

 

[keith_a]

Mathew , I had troubles with mine on my 420. It caused the same issues only i let it go for the better part of a season of mowing. I removed it and then looked at the little circuit board , I found a diode had fried. Went to a local computer repair store got a similar diode, soldered it right over the existing one, and re-installed. That was 2 years ago this spring , that 420 has ran like a dream ever since.
Keith

 

[E Behm]

If you have the glass fuses, Get them out of there and install the plastic ones. I have had lots of problems with them.