9 replies to this topic

[garnel]

I've had a single relay on two different 16 channel Sainsmart boards fail. Removing and replacing the entire board - moving fifty two wires from one board to a new board is a pain and error prone. 

My plan is to go to mosfets - but until then, took another Sainsmart relay board with one bad relay, wired power and ground to it and moved three wires from the defective relay in the old board to a good relay on the other board. This leaves 14 good relays as spares.  If/when another relay fails - only three three wires need to be moved.

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Update: Just discovered that my issue probably was caused by a suppression diode - this time I replaced the diode and the solenoid just case. Then measured the removed diode - it was open - wide ass open - no backflow protection for that channel probably caused the failures. In both cases the Sainsmart relay contacts became resistive, dropping the 12vdc across the relay to less than half.

Edited by garnel, 15 November 2021 - 11:37 PM.

[wiesshund]

Silly question
Cant you socket those relays?
Or not enough room on the board?

[garnel]

Silly question
Cant you socket those relays?
Or not enough room on the board?

These boards at $15 each are so cheap - and it's so much easier to install a second Sainsmart module and just switch the wiring over from the failed relay. No soldering to remove and replace a relay. Also not sure sockets are made for the output relays.

 

I could have saved myself a lot of work by "front to back" measuring the suppression diodes with an ohm meter after installing them to make sure none were open!

[STV]

Diode or not - those sainsmart relays have a finite duty cycle.   They just stop working after a while.   Move to mosfets is the best solution, it's what many people have done.

[garnel]

Diode or not - those sainsmart relays have a finite duty cycle.   They just stop working after a while.   Move to mosfets is the best solution, it's what many people have done.

That's my plan - just using the Sainsmart boards temporarily while ordering the mosfet drivers -  and getting them working prior to installing them in the table.

[STV]

Here's my SS boneyard:

 

 

(edit)

And the green boards that replaced it:

 

Edited by STV, 16 November 2021 - 06:12 PM.

[garnel]

Here's my SS boneyard:

 

 

(edit)

And the green boards that replaced it:

 

Are you still using a LEDWiz to drive the mosfet boards?

[STV]

 

Here's my SS boneyard:

 

 

(edit)

And the green boards that replaced it:

 

Are you still using a LEDWiz to drive the mosfet boards?

 

 

No.   Using the kl25z with pinscape, that signals the mosfets. 

[garnel]

I have as many Sainsmart boards with individual dead relays as STV.  Just finished hooking up my flippers to an IRF540N (Red board) connected to my ledwiz. Works great but I'm going to run it this way for a couple of weeks to make sure it's reliable before moving the rest of the toys from the Sainsmart.

To use the Red mosfet board an inverter with an open collector output with a pullup resistor needs to be added between the ledwiz output and the IRF540N input. I used a 74LS06 with a 5.1K ohm resistor pullup on each output. The resistor value was chosen using the 10X rule - the pullup resistor should be at minimum 10 times the input impedance of the device it is driving. The input impedance of the Red IRF540N is 470 ohms.

Installed the mosfet board this morning and connected both flippers.

Edited by garnel, 05 December 2021 - 07:24 PM.

[garnel]

Decided not to use the red mosfet boards - the interface to make them work requires way too much soldering with tiny components - my eyes just aren't what they once were. Decided to go with LED RGB booster amplifiers. Bought the following ones on Amazon.

https://smile.amazon...product_details

Each one drives three 12 volt SW-3 starter motor relays. The SW-3's each draw 3 Amps while each of the LED amplifiers have a 4 Amp capacity. These work directly with the Ledwiz as is - and so far they work great.

 

I've ordered some of these to try:

https://www.ebay.com/itm/251918116582

The reviews are a bit iffy in this product, but I'll give them a try anyway and update this after.

Update: Don't waste your money on these small inline amp's - they just don't have the suds - they are 4 amp total, not each channel.

 

Anyway, the Sainsmart board is OUT of my cabinet.

 

Update: Installed six of the 3 channel 12 amp Amplifiers - they worked great - no problems.

 

Update: Found physically smaller four channel 24 amp RGBW LED Amplifiers in ebay, purchased four of them to replace the six three channel amplifiers just to clean up the wiring and simplify things a bit. Found they require a larger 12vdc power supply as they caused my 12v, 7 amp arcade supply to crowbar. Replaced it with a 30 Amp supply  and everything works well.

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Attached Files

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Edited by garnel, 12 January 2022 - 10:13 PM.