Ever get a unit torn down completely to replace a part and discover you had
ordered a 'similar but different" part instead of the correct one?

Or grabbed the wrong unit off the shelf, tore it down only to discover you'd
ordered the part for the other (almost identical looking) unit nearby?

Yup. Did that yesterday, and it wasn't pretty. I'd ordered a complete main
board (sheet of boards actually) for a Yamaha RX-A1040 because the outputs
etc weren't available and it was under warranty, so it was agreed that I
should order the whole magilla.

Unfortunately I tore down an RX-A2010 before the mistake was discovered.

At least the only thing lost was the hour or so it took to put that one back
together and commence the repair on the correct unit.

Not my finest moment...


Mark Z.

Another thing is knowing which part is the old one.

I have been known to use used parts. So I got this RPTV needs a HV block. (thing that distributes the HV to the three CRTs and divides down the focus and G2 voltages)

The wires go all over the place so it takes a little time to get it out and in. So I get it out. Then I picked up the same part and put it back in.

I keep track of the used parts pretty well. This one came from a working unit that had weak CRTs. Took a little head scratching but it finally dawned on me that I had reinstalled the bad part.

Now, when I know a part is bad I do something to it. Cut off a wire of something. Anything to distinguish it.

If it had been a new part, no problem, but these two had about the same amount of dust on them and were pretty much identical.

wrote in message
...
Another thing is knowing which part is the old one.

I have been known to use used parts. So I got this RPTV needs a HV block.
(thing that distributes the HV to the three CRTs and divides down the
focus and G2 voltages)

The wires go all over the place so it takes a little time to get it out
and in. So I get it out. Then I picked up the same part and put it back
in.

I keep track of the used parts pretty well. This one came from a working
unit that had weak CRTs. Took a little head scratching but it finally
dawned on me that I had reinstalled the bad part.

Now, when I know a part is bad I do something to it. Cut off a wire of
something. Anything to distinguish it.


Done that also. Got to the point I carry a felt tip pen and mark the old
one with a O or OLD on it. May just put an X or sometimes if the old part
is put back in because it was not bad I put number on it.

Some of the computer controlled processes use what is called a PLC that has
lots of modules about the size of the cable modems that plug into a rack.
They will have a few small switches or jumpers inside them and the new one
will need to be set the same as the old one. Need to keep up with which is
the old part and which is the new one so the switches can be set correctly.

On Friday, December 18, 2015 at 11:58:31 AM UTC-5, Ralph Mowery wrote:

Some of the computer controlled processes use what is called a PLC that has
lots of modules about the size of the cable modems that plug into a rack.
They will have a few small switches or jumpers inside them and the new one
will need to be set the same as the old one. Need to keep up with which is
the old part and which is the new one so the switches can be set correctly.

Worked at a plant that used Allen Bradley PLCs.

The program resided in memory but there was a backup EPROM in the cabinet.

You could also type it in by hand but it was thousands of lines of ladder logic, any line of which could point to any other, it would take weeks.

So we lost the program in a power surge or something. No problem, pop the EPROM in and download the program.

Meanwhile the production manager is screaming we're going to miss the ship date and lose the customer. No sense of humor, those guys.

Here's the catch: on some PLCs download the program means install it FROM the EPROM, but on these A-Bs download meant install it TO the EPROM. So we downloaded the empty program into the EPROM, erasing it.

No problem, we have a spare safely locked in the maintenance office. Notice I said A spare, as in, one. You already know what we did, popped that one in the PLC and erased that one too.

"Tim R" wrote in message
...

Worked at a plant that used Allen Bradley PLCs.

The program resided in memory but there was a backup EPROM in the cabinet.

You could also type it in by hand but it was thousands of lines of ladder
logic, any line of which could point to any other, it would take weeks.

So we lost the program in a power surge or something. No problem, pop the
EPROM in and download the program.

Meanwhile the production manager is screaming we're going to miss the ship
date and lose the customer. No sense of humor, those guys.

Here's the catch: on some PLCs download the program means install it FROM
the EPROM, but on these A-Bs download meant install it TO the EPROM. So
we downloaded the empty program into the EPROM, erasing it.

No problem, we have a spare safely locked in the maintenance office.
Notice I said A spare, as in, one. You already know what we did, popped
that one in the PLC and erased that one too.


We had about 40 or 50 of the AB PLC 5s in the plant. Some of the older
ones. Just glad that they finally came out with some computer software that
could be loaded on a laptop, and then later it was on a network where we
could sit in one room and look at most of them. This I hated about the ABs
were we were suspsoe to power the thing down if changing out an input or
output card. When running a continious process 24/7 we did not want to shut
down a PLC rack.


I liked the Fisher/Provox stuff much beter. We could hot swap any one crd
at a time without shutting off the other sutff.

In article ,
says...
Done that also. Got to the point I carry a felt tip pen and mark the
old
one with a O or OLD on it. May just put an X or sometimes if the old part
is put back in because it was not bad I put number on it.

Sounds like my late father. If the car workshop said they would replace
a part he would put a small mark on the old one in situ. If the mark was
still there after he was charged for a replacement he would give them
hell!

Mike.