Diesel synch module failed

ZZ13

ZZ13

Well-Known Member
Nov 25, 2009
5,329
Lady's Island, SC
Boat Info
2001 400 Sedan Bridge
Engines
Cummins 450 Diamond
Looks like the starboard side of my diesel synch module failed. It’s the hockey puck thing under the helm that takes the pickup pulse signals and converts that to voltage for the synch gauge. What’s the history of that thing? No one makes the diesel version anymore and hasn’t for a long time. Did diesel boat manufacturers quit designing them into the helm at some point? Looks like Sierra still makes a gas version.

I guess I’ll finally take it and the gauge out and put my boost gauge in its place. It’s a perfect fit for the hole.
 
Yea - with the advent of the electronically controlled engines those devices and gauges went away. Not too long ago someone else was having the same issues also on this forum; might try to fine that and what their solution was.
Try and call Max Marine Electronics in Ft Lauderdale - they have a bunch of that kind of stuff.
 
ttmott said:
Yea - with the advent of the electronically controlled engines those devices and gauges went away. Not too long ago someone else was having the same issues also on this forum; might try to fine that and what their solution was.
Try and call Max Marine Electronics in Ft Lauderdale - they have a bunch of that kind of stuff.
Click to expand...
Good idea. I was also going to try Marine Connections in Ft Pierce. But the more I noddle on it the more I think I’ll just “modernize” the look with the boost gauge. I have Aetna tachs so I don’t really need a synch gauge. I’ll just have to train my brain not to have one.
 
ZZ13 said:
Good idea. I was also going to try Marine Connections in Ft Pierce. But the more I noddle on it the more I think I’ll just “modernize” the look with the boost gauge. I have Aetna tachs so I don’t really need a synch gauge. I’ll just have to train my brain not to have one.
Click to expand...
I wonder if it’s repairable?

I’ve never looked at one, but if you pull it, I’d be interested in dissecting it to see if they can be resurrected, or duplicated. My guess is there are some combination of leaking capacitors or blown diodes/resistors. However, they may have potted them such it will be impossible to access.

However, if my sync gauge dies, I will miss it, but I like the idea of boost or even turbocators there instead.
 
dtfeld said:
I wonder if it’s repairable?

I’ve never looked at one, but if you pull it, I’d be interested in dissecting it to see if they can be resurrected, or duplicated. My guess is there are some combination of leaking capacitors or blown diodes/resistors. However, they may have potted them such it will be impossible to access.

However, if my sync gauge dies, I will miss it, but I like the idea of boost or even turbocators there instead.
Click to expand...
As usual I’ll tear it apart when I get it out. It’s not easily dissected. It’s one big molded piece of plastic. Will have to cut it apart.
 
ZZ13 said:
As usual I’ll tear it apart when I get it out. It’s not easily dissected. It’s one big molded piece of plastic. Will have to cut it apart.
Click to expand...
That’s what I suspected. Grrrrrr. Mine is probably not far behind yours.
 
The module might not be that hard to replicate. It seems to simply convert the tach pulses into DC voltage - the higher the rate of pulses the higher the voltage; my guess. The gauge then shows the differential in voltage between the two engines.
 
dtfeld said:
That’s what I suspected. Grrrrrr. Mine is probably not far behind yours.
Click to expand...
Maybe not. I probably helped it along. I stuck a screwdriver into the centering hole to adjust the pot with power on and it slipped off the pot onto the board. It became a different kind of failure after that. I probably shorted something inside with the tip of the screwdriver.
 
ttmott said:
The module might not be that hard to replicate. It seems to simply convert the tach pulses into DC voltage - the higher the rate of pulses the higher the voltage; my guess. The gauge then shows the differential in voltage between the two engines.
Click to expand...
Is this the type of thing you mean? Or is this something different? Would be real easy to put two of these in a box and make your own synch module. The output voltage of 0-10v is the right range for the existing synch gauge.
 
ZZ13 said:
Nevermind. I just noticed the output is analog, not DC.
Click to expand...
Actually, that module is likely very similar to what’s in the puck. The issue is you would need 2 PWM inputs with a comparative function and the correct voltage out. No idea what that gauge actually uses.
 
Took it off. Turns out it’s two pieces held together by the metal grommets that double as mounting holes. Will remove the grommets and take a look inside.

IMG_7038.jpeg
 
There it is. Not a whole lot I can do with that. You can see in the second picture that my too wide screwdriver scraped up the area on and around the centering pot pretty good. There is a trace just to the right of the pot where there is a gold glow from the screwdriver scraping that. Could be it broke the trace and now that is an open. That’s what I get for thinking I have a small enough screwdriver when I really didn’t.
IMG_7042.jpeg
IMG_7040.jpeg
 
Looks like you might have scraped the green coating off a little but the trace looks to be fine.

Post a picture if the back so we can look at the solder joints.
 
I gave up on the synch stuff. I clearly damaged the module. More debug revealed that it works normally if only one engine is running (either one)but with both running the needle pegs permanently to center, regardless of the rpm difference. So today I ripped all the synch gauge stuff out. Installed the boost gauge. May paint the plastic bezel of the boost gauge to match it with the chrome bezels of the other gauges. I wanted to do this when I bought the boost gauge but I let CSR members talk me out of it (Ha!).
IMG_7044.jpeg
IMG_7045.jpeg
 
You must log in or register to reply here.

Forum statistics

Threads
113,182
Messages
1,428,083
Members
61,089
Latest member
KDKING
Back
Top