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OT: Tennis ball machine PCB testing

Yeah, not great, but those things are tough to replace. Best method is hot air gun, which I would assume they actually did use.

The list of semiconductors replaced makes sense. The other items may be things observed to be bad, don't know.

Yeah, the black pushbutton item back a page is a circuit breaker. Perfectly OK item, and the thing in line looks like "spade" connectors to me.

The proof is in the using.

If they added heatsinks, they know there is a problem, and the result should be better performance with overcurrents. Looks like they added the heatsinks to the backside, which is less than ideal, but should improve things. There seem to be a number of vias around the replaced devices, which act as heat paths to the backside. There is no place to put the heatsink on the same side with the devices.

Don't know those devices, and did not look them up. However, a number of newer MosFets have ridiculously low "on" resistances, and dissipate very little. Some are in the range of a few thousandths of an Ohm. Years ago, Peavey made a thousand watt class-D amplifier, with each channel using a pair of physically small MosFets. They did not even have heatsinks, but they did have a fan blowing on them.

Due to the very low "on" resistance (and fast switching), they dissipated only a small amount of power, so the fan was good enough. I hope Peavey interlocked that fan, though, since without it, there would be a serious problem if the amplifier was operated. :eek:
 
Nice data points ... I suspect they are making a decent profit on those services but that's the thing I always tell others .. what you don't t know can harm you, cost you money and in some cases kill you ...
This experience has motivated me to learn how to troubleshoot these electronics problems myself more so than ever. It is a skill and gift that seems to keep on giving.
Thanks for sharing, I've already saved it and will look deeper into a few of those data points you mentioned.
Based on what I've learned
I will not be recommending this brand and would luv to one day attempt to make my own for pickle balls. ... I just hope this holds up a bit. I did notice the main two larger motors on these machines seem to be rated well.
If this machine bites the dust those motors are definitely worth keeping around.
 
Yeah, not great, but those things are tough to replace. Best method is hot air gun, which I would assume they actually did use.

The list of semiconductors replaced makes sense. The other items may be things observed to be bad, don't know.

Yeah, the black pushbutton item back a page is a circuit breaker. Perfectly OK item, and the thing in line looks like "spade" connectors to me.

The proof is in the using.

If they added heatsinks, they know there is a problem, and the result should be better performance with overcurrents. Looks like they added the heatsinks to the backside, which is less than ideal, but should improve things. There seem to be a number of vias around the replaced devices, which act as heat paths to the backside. There is no place to put the heatsink on the same side with the devices.

Don't know those devices, and did not look them up. However, a number of newer MosFets have ridiculously low "on" resistances, and dissipate very little. Some are in the range of a few thousandths of an Ohm. Years ago, Peavey made a thousand watt class-D amplifier, with each channel using a pair of physically small MosFets. They did not even have heatsinks, but they did have a fan blowing on them.

Due to the very low "on" resistance (and fast switching), they dissipated only a small amount of power, so the fan was good enough. I hope Peavey interlocked that fan, though, since without it, there would be a serious problem if the amplifier was operated. :eek:
Thank you sir
 








 
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