Pak 200i – Tweco PAK 200i User Manual
Page 128
PAK 200i
A-48
APPENDIX
Manual 0-5335
Either Arc Starter
5. /RAS ON signal not on. CCM sends active low signal “ /RAS ON” over the 40 pin ribbon cable on pin
16 to the Relay & Interface board. On the relay board RAS Control relay (K2) closes (RF ON LED, D23 on)
sending 120 VAC to J8-3 with return on J8-11. From here it either goes to the HF transformer T2 (AC 200XT
and PAK 200i) or to J59 as described above.
a. Measure the signal “/RAS ON” on pin 16 of the 40 pin ribbon cable relative to TP1 on either the CCM
I/O board or the Relay board. If it is low (less than 1V) skip to step 6. Otherwise continue this step.
NOTE
If the CCM thinks there is already a pilot it would not enable the HF. Pilot board has a current sensor that sends
a differential analog pilot current level signal to the Relay board which in turn passes that signal to the CCM. On
the Relay board D11 LED “Pilot Current Detected” or just “PILOT” lights if it sees a signal from the pilot board.
Reasons why RAS Control relay would not close:
6. Pilot current flowing. There actually is pilot current flowing somewhere. Unlikely as it would normally set
the 208 fault but we have to rule it out.
a. Disconnect J41 on the Pilot board, if HF still doesn’t fire and the Relay board Pilot LED, D11, is still
on, it’s due to a fault in the detection circuits.
7. Faulty detection circuit. There isn’t any pilot current but a fault in the circuits measuring pilot current is
indicating there is current.
a. Measure between pins 8 (-) and 9 (+) on the Pilot ribbon cable from Relay board J3 to Pilot board J42. If
there is no pilot current it should be zero. Anything else indicates the Pilot board current sensor is faulty
causing the Relay board D11 to be on. Replace the Pilot board assembly.
b. If the Pilot current signal on the pilot ribbon cable was zero, measure between pins �3 (-) and �5 (+) on
the 40 pin ribbon cable between the Relay board and the CCM. This would also normally be zero if there
is no pilot current. Anything else would indicate the Relay board is faulty.
Art # 12307
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23
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40
J23
TO RELAY BOARD
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40
J4
From I/O PCB
24VDC_SW
D21
GREEN
D23
RF ON
1
5
3
4
K2
RAS CONTROL
120
VA
C
120 VAC to RAS
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
J8
120
VA
C
R
ET
120 VAC_1
From J9-1
120 VAC_RET
From J9-7
CCM I/O Board
Relay & Interface Board
1
2
3
4
5
6
7
8
9
10
11
12
13
14
J59 - RAS
(98)
(99)
T2
120 / 6000 VAC
(98)
(99)
6.5K 1W
6.5K 1W
AC200XT only
(Rear Panel)
TP1
GND
TP1
GND
/ RAS ON