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1/2-HP Block Grinder m-397.19440 - post mortem

torqueman2002

Well-known member
Joined
Jun 3, 2009
Messages
6,138
Location
SE Michigan
The CL ad said: "Spins free but does not run. Changed the capacitor but didn't fix it."

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Now who would be crazy enough to buy a grinder that doesn't work?

Well, it sat there for a long while; OK < 7 days. But how long can a guy be expected to hold out?

I've payed less than $20 for a Block, but not for a darn near complete 1/2-HP Commercial Crown Top.
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It is well used and needs a good clean up, and maybe respray. But heck it's been in use since, well ... I can't tell for sure, but it looks like APR 17, 1975 A.
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With the bottom cover off, there are a few apparent things that aren't OEM. The cap is loose and at an angle, the relay is also loose and there's evidence that an attempt was made to open the sealed cover, and the lamp wires are disconnected.
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New (left) and old caps.
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The power cord, power switch, wiring, and terminal condition checked out OK.

When powered-up, the Block indeed did not: run, try to start, hum, dim the lights. Hmmmmm, ....

It could be the relay, but they are very reliable. OK, time for the field coils/windings to be checked.

Not good news. Only the Red and Blue conductors show continuity, the others are OPEN.
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Time to go deeper. Another bad sign. Can you see it?
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Yup, a dark section of winding.

Well, here's a repairable OPEN.
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The ends were cleaned and prepped for solder. But 1st, a check for continuity.
:( Same results. A further look is needed.

The other side of the winding assembly, 2 more opens and a lot of crispy wire.
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At this point, I decided it was a lost cause and went into investigation mode.

I pulled the start-up windings (thin wires) to see what was under them.

Lots of carnage and many open spots in the winding.
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Well, I've watched enough forensic tv to know you don't stop at a point like this, when the patient, errr victim is still on the table.

CAUTION.
Viewer discretion is advised.
What you are about to see may be upsetting to some viewers.
Strong graphic anatomical content.
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I did my best. But it was too late.

Maybe if the user had turned OFF the switch at the first sign of smoke.

Or, if there had been a fuse installed.

Thanks for looking.
 
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torqueman2002

Well-known member
Joined
Jun 3, 2009
Messages
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Location
SE Michigan
Ouch. May as well part it out. I have the same model (iirc) and like it very much.
Yea, I have some Blocks in my shop on the donor list.

I just need to decide which of my Blocks are going to get what.

It will probably wind up, this guy giving-up his parts, rather than receiving a field coil/winding from one of the other in my shop.
 
Last edited:

ganymede

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Nov 29, 2012
Messages
2,332
Location
New England
Still, $20 for parts that you can't get anywhere else is a good deal.

This.
How many grinders have we all seen with missing tool rests, eye shields, cover plates missing on the sides of the wheel guards, completely illegible id plate, housing rusty etc?
 
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torqueman2002

Well-known member
Joined
Jun 3, 2009
Messages
6,138
Location
SE Michigan
This.
How many grinders have we all seen with missing tool rests, eye shields, cover plates missing on the sides of the wheel guards, completely illegible id plate, housing rusty etc?
Exactly.

Here's just 1 sad one waiting his turn in my shop for parts.
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