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Help finding this board for a sliding gate motor
- Thread starter josh1112
- Start date
Well as for the features it has it takes in input from a photo sensor that stops it from closing if someone breaks the beam. The gate itself also has magnetic limit switches which stops the gate at the correct moment. Apart from that it is pretty standard. The first problem that occurred was that the fuse holder had become detached which I had fixed and tested. It seemed to work but the motor never ran continuously. Now the board has no power at all.
Hmmmm - almost entirely discrete parts (one IC) so should be simple enough to repair.
Those relay contacts looks a bit dodgy though - suspect contact cleaning and/or replacement relays will fix the issue. Close pics needed - hopefully with the relay clear plastic covers off.....
Those relay contacts looks a bit dodgy though - suspect contact cleaning and/or replacement relays will fix the issue. Close pics needed - hopefully with the relay clear plastic covers off.....
I'm not sure that the problem is with the relays as when the board was functional the relays seemed to be working properly. The current issue is that the board itself has no power.
That would appear to make it relatively easy to trouble shoot and repair if there is no power.
A little reverse-engineering should help pin it down.
What about the voltage regulator, any voltage in? any voltage out?
It seems like much of it is descrete logic, if so, a small micro could have done virtually all the logic functions seen for a much smaller board..
BTW what is the 18pin IC No.?
M.
SIR josh1112 . . . . .
It appears that they are using two completely separate power supplies on your board. The larger yellow potted
transformer is probably just for your 24VAC for that approximate . . .or less . . . level of DC then created on the
board for relay drive by the 4 diodes in the PALE BLUE rectangle and the RED CIRCLE electrolytic filter cap.
If none of your 4 YELLOW circled indicator LED's PLUS the one near the right top corners transformer light,
that supply also probably serves them.
( ( ( With high probability that last green one, near the YELLOW transformer is a power presence indicator. ) ) )
The other isolated power supply for logic functions seems to be the BLUE transformer that feeds the BLUE electrolytic which then feeds into the YELLOW rectangle 5V 3 term Regulator 2, which may just use a pass transistor for pre reg 1 function or even just a zener diode .
The 5VDC then feeds the left top corners logic circuitry.
FAILURE ANALYSIS . . . . .high probability
Your electronics is probably still OK, with the end fault being related to time related attrition of the electro-mechanical aspects of the unit.
Look vewy-vewy-vewy carefully at the GREEN / PINK rectangle marked up pair of motor direction reversing relays.
Each uses a single pole double throw configuration of its relay contacts.
Refer to the YELLOW arrow + dots going to he relay contacts.
I have MAGGED this up such that you can now easily see that the right contact sets of the upper relay have been arcing to the extent that contact metal has transmigrated on up to the clear plastic cover and makes a quite noticable deposition of metal .
The same is true of the companion relay, just below it, but it has not yet degraded to that bad of an extent.
FACTOID . . . .
If these contacts reliability have declined to the extent of not always making positive contact a resultant paralleling or anti phasing of the AC motor windings can cause a hummmmm and groan of the motor and a popping of the fuse.
If done many times, the thermal protection within the YELLOW power transformer may have open circuited its primary winding.
INFO TIME . . for .feedback . . . .
How many fuses were placed in the unit and blown ?
Was the first fuse a soft or hard blow ? . . . a soft blow is where there is still a viewable fusing metal link inside.
A medium blow is where the opened link gap is wider . . . a hard blow is where there is even a blackening to the inside of the glass casing.
Would that be a 20 amp fuse ?
What info is on the actuator motor label , giving us relevance to its voltage, current or wattage ?
MORE INFO NEEDED . . . .
The capacitances and voltage ratings of the 4 RED BLUE and GREEN pairs of electrolytics.
Is REG 2 markings indicative of being a 7805 family of 5 V regulator ?
They may have "customized" the U1 microprocessor's ID by defacing its surfactal markings.
(BUT I think that it will not even be involved.)
Does this unit additionally use a key FOB type of remote transmitter ?
MAGGED UP COMPONENT SIDE BOARD REFERENCING . . . .
73's de Edd
.
It appears that they are using two completely separate power supplies on your board. The larger yellow potted
transformer is probably just for your 24VAC for that approximate . . .or less . . . level of DC then created on the
board for relay drive by the 4 diodes in the PALE BLUE rectangle and the RED CIRCLE electrolytic filter cap.
If none of your 4 YELLOW circled indicator LED's PLUS the one near the right top corners transformer light,
that supply also probably serves them.
( ( ( With high probability that last green one, near the YELLOW transformer is a power presence indicator. ) ) )
The other isolated power supply for logic functions seems to be the BLUE transformer that feeds the BLUE electrolytic which then feeds into the YELLOW rectangle 5V 3 term Regulator 2, which may just use a pass transistor for pre reg 1 function or even just a zener diode .
The 5VDC then feeds the left top corners logic circuitry.
FAILURE ANALYSIS . . . . .high probability
Your electronics is probably still OK, with the end fault being related to time related attrition of the electro-mechanical aspects of the unit.
Look vewy-vewy-vewy carefully at the GREEN / PINK rectangle marked up pair of motor direction reversing relays.
Each uses a single pole double throw configuration of its relay contacts.
Refer to the YELLOW arrow + dots going to he relay contacts.
I have MAGGED this up such that you can now easily see that the right contact sets of the upper relay have been arcing to the extent that contact metal has transmigrated on up to the clear plastic cover and makes a quite noticable deposition of metal .
The same is true of the companion relay, just below it, but it has not yet degraded to that bad of an extent.
FACTOID . . . .
If these contacts reliability have declined to the extent of not always making positive contact a resultant paralleling or anti phasing of the AC motor windings can cause a hummmmm and groan of the motor and a popping of the fuse.
If done many times, the thermal protection within the YELLOW power transformer may have open circuited its primary winding.
INFO TIME . . for .feedback . . . .
How many fuses were placed in the unit and blown ?
Was the first fuse a soft or hard blow ? . . . a soft blow is where there is still a viewable fusing metal link inside.
A medium blow is where the opened link gap is wider . . . a hard blow is where there is even a blackening to the inside of the glass casing.
Would that be a 20 amp fuse ?
What info is on the actuator motor label , giving us relevance to its voltage, current or wattage ?
MORE INFO NEEDED . . . .
The capacitances and voltage ratings of the 4 RED BLUE and GREEN pairs of electrolytics.
Is REG 2 markings indicative of being a 7805 family of 5 V regulator ?
They may have "customized" the U1 microprocessor's ID by defacing its surfactal markings.
(BUT I think that it will not even be involved.)
Does this unit additionally use a key FOB type of remote transmitter ?
MAGGED UP COMPONENT SIDE BOARD REFERENCING . . . .
73's de Edd
.
Last edited:
....that's why I said the relays were 'suspect'.
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