SS Chassis Problem

[8270king]

I have a chassis that the sweep and table will run but it wont cycle.

I think the heat sink might be the problem.

Would you think the varisitor or the power diode is bad.

And how would you check these with a multimeter?

Thanks in advance.

[Coors]

Re: SS Chassis Problem

Varasitor. is usually the prob. if it was the power diodes it would just blow the F1. put tester on continuity, powerdiodes should have infinity one way, and nothin the other. the varasitors i honestly dont know how to check, but i had the same prob with the table only, replaced the varasitor for the table, and Wa-Lah. could also be the wires leading from the motherboard to the heat sink. tho i doubt both wires went at the same time, but i could see the varasitors if it got a surge

[Coors]

Re: SS Chassis Problem

also the pwoer diodes on the outside have continuity one direction, the one in the middle has continuity the opposite, normally the 2 outside diodes that go

[Tall Paul]

Re: SS Chassis Problem

King, will it complete the cycle if you run the sweep down to 66 degrees. If so , Iwould guess something in instructomat.

[triac]

Re: SS Chassis Problem

King,

General rule I go by. If you can energize sweep/table the relays with the cams (chassis @ zero) the varisitors are ok. They are nothing more than a surge protector for the relay.

If you can run the sweep thru the SW switch but not the SA cam and you have no cycle, then chances are you’re stuck in shadow bowl. To confirm this …disconnect the thin gray wire on the T2 and tape it off. This isolates the instructomat outside the chassis and to the PC Board.

If you’re sure it’s in the chassis, take a look at the C2A sockets and swap PC board.

Triac

[Rep]

Re: SS Chassis Problem

Excellent posts about the power diodes coors. I had to change some in an old chassis I rebuilt last summer. I doubt it's them IMHO King. Just out of curiosity did you swap out the M relay in the problem chassis? I had one go once resulting in what you describe, could run sweep and table but no cycle. Just an idea if ya haven't tried that yet. Keep us posted

[8270king]

Re: SS Chassis Problem

Originally posted by triac:
King,

General rule I go by. If you can energize sweep/table the relays with the cams (chassis @ zero) the varisitors are ok. They are nothing more than a surge protector for the relay.

If you can run the sweep thru the SW switch but not the SA cam and you have no cycle, then chances are you’re stuck in shadow bowl. To confirm this …disconnect the thin gray wire on the T2 and tape it off. This isolates the instructomat outside the chassis and to the PC Board.

If you’re sure it’s in the chassis, take a look at the C2A sockets and swap PC board.

Triac

<font size="2" face="Verdana, Helvetica, sans-serif">Positive it is in the chassis.
I taped the gray wire on the T2 and it runs.
What do I do now?

Thanks again!
JK

[triac]

Re: SS Chassis Problem

Are you saying the machine now has a cycle with the gray wire disconnected and taped? If so you can leave it that way, but you wont have shadow bowl or the frame counter wont work at the front counter.

If you need one or both of these functions and you have moved the chassis to confirm its in the chassis then you have a couple of options to look at.

First did you swap the Omega Tek board?

With the Mk 70 in you will have high resistance to gray wire (like 2M) then reverse probes you should have nothing.

Make sure gray wire does not have continuity to ground with the MK 70 pulled. If so pull SP relay and recheck. If it still has continuity physically trace the wire looking for a grounded source.

With the Mk 70 pulled Check:

Dont worry about diode under the SP relay (at this time) it only comes into play when the SP is energized (this is what makes the frame meter work when SP energizes for spotting). Check the connections to the SP socket that they are not touching and that they have good soldier.

Check the mother board at the connection PC1-5 and make sure pins are not touching each other.

Take ohms reading on the T2 secondary with wires disconnected and compare the readings to another T2. If you get zero or infinity resistance you got a bad T2.

Let me know if you have tried all this and still jacked up and Ill rack my brains some more.

Triac

[8270king]

Re: SS Chassis Problem

Originally posted by triac:
Are you saying the machine now has a cycle with the gray wire disconnected and taped?
**Yes.
If so you can leave it that way, but you wont have shadow bowl or the frame counter wont work at the front counter.
**We don't use shadow except to run the lanes and clean Sure Pik belts at the same time.
If you need one or both of these functions and you have moved the chassis to confirm its in the chassis then you have a couple of options to look at.

First did you swap the Omega Tek board?
**I have tried 3 or more Omega Tek boards.
With the Mk 70 in you will have high resistance to gray wire (like 2M) then reverse probes you should have nothing.

Make sure gray wire does not have continuity to ground with the MK 70 pulled.
**I will check this Monday.
If so pull SP relay and recheck. If it still has continuity physically trace the wire looking for a grounded source.

With the Mk 70 pulled Check:

Dont worry about diode under the SP relay (at this time) it only comes into play when the SP is energized (this is what makes the frame meter work when SP energizes for spotting).
**I have clipped all the diodes under the SP relay in all chassis.
Check the connections to the SP socket that they are not touching and that they have good soldier.
**None.
Check the mother board at the connection PC1-5 and make sure pins are not touching each other.
**Noted.
Take ohms reading on the T2 secondary with wires disconnected and compare the readings to another T2. If you get zero or infinity resistance you got a bad T2.
**Will do Monday.
Let me know if you have tried all this and still jacked up and Ill rack my brains some more.

Triac

<font size="2" face="Verdana, Helvetica, sans-serif">Thanks again.

[maister]

Re: SS Chassis Problem

nice one triac.
maister.

[8270king]

Re: SS Chassis Problem

Ok.

It is not the SP relay.

I traced the grey wire to the SP socket then to the mother board.

I scraped between the contacts on the mother board but it still will not run with the grey wire hooked up.

It does read cont. to ground.

It is not in the board for sure and not in the machine or AMC box.....it is in the chassis.

[triac]

Re: SS Chassis Problem

Did you pull the Mk-70 before checking continuity to ground? With the board in it will high resistance (about 2M) to ground, with board out should be nothing.

Check very carefully where the short gray wire comes from the SP socket to motherboard, that those pins are not touching.

Triac

[8270king]

Re: SS Chassis Problem

If I pull the grey wire off that goes from the T2 to the S relay socket.....what will happen if the machine is put in Instructomat at the Frameter?

[triac]

Re: SS Chassis Problem

You wont have shadow even if the machine is put in instructomat at the desk.

Does you gray wire still have continuity to ground with Mk pulled

[8270king]

Re: SS Chassis Problem

Originally posted by triac:
You wont have shadow even if the machine is put in instructomat at the desk.

Does you gray wire still have continuity to ground with Mk pulled

<font size="2" face="Verdana, Helvetica, sans-serif">I will check with the Mk pulled tomorrow.