Beseler stabilized power supply DGA for the Dual Dichro and timer power

[DonF]

I have a Beseler 23 with Dual Dichro head with the mentioned external stabilized power supply. The supply has a square multi-pin connector for connection to the enlarger, an AC power cord for AC input, a socket for a timer, and a short AC power cord for connection to the timer output.

The trouble with this arrangement is that it is necessary to switch on the power supply in order to power the timer, causing the loud continuous cooling fan in the Dual Dichro head to run. I would like to be able to run the timer for other non-enlarger tasks without turning on the fan as well.

I had the idea of simply plugging the timer into another wall outlet, rather than the back of the power supply. I don't think the socket for the timer provides stabilized power to the timer, nor is it needed at the timer output. I believe the 24vac stabilized lamp voltage is sent to the enlarger through the square connector and that the 120vac timer output simply drives a relay in the head that switches the lamp on and off via a relay.

Plugging the timer directly into the wall bypasses the supply, but stabilized power should still be supplied to the lamp.

I have been unable to locate a schematic for the supply, but it seems this should work. Any thoughts?

Best regards,

Don

 

[mshchem]

I have a Beseler 23 with Dual Dichro head with the mentioned external stabilized power supply. The supply has a square multi-pin connector for connection to the enlarger, an AC power cord for AC input, a socket for a timer, and a short AC power cord for connection to the timer output.

The trouble with this arrangement is that it is necessary to switch on the power supply in order to power the timer, causing the loud continuous cooling fan in the Dual Dichro head to run. I would like to be able to run the timer for other non-enlarger tasks without turning on the fan as well.

I had the idea of simply plugging the timer into another wall outlet, rather than the back of the power supply. I don't think the socket for the timer provides stabilized power to the timer, nor is it needed at the timer output. I believe the 24vac stabilized lamp voltage is sent to the enlarger through the square connector and that the 120vac timer output simply drives a relay in the head that switches the lamp on and off via a relay.

Plugging the timer directly into the wall bypasses the supply, but stabilized power should still be supplied to the lamp.

I have been unable to locate a schematic for the supply, but it seems this should work. Any thoughts?

Best regards,

Don

What sort of timer are you using ? If it's a ordinary timer you should be able to plug in anywhere to use . If it has a household plug on it it should be fine on it's own I have a 4x5 version of this as a backup .I don't remember any special timer. The old Beseler enlargers had a outlet on the motor elevation motor that required a switch or timer that would close the circuit.

 

[DonF]

I was using a Gralab-style analog dial timer, but I just built my own f/stop digital timer. They work the same from the enlarger’s perspective, switching 120vac to the enlarger for controlling the 24vac to the lamp via a relay.

The only issue I can think of is that there might be some consequence of supplying line voltage to the lamp control relay in the head without the 24vac lamp voltage present. The design of the power box makes this impossible if the built-in timer power socket is used. The relay doesn’t actuate if power from the timer alone is applied, so I don’t think there is any danger in my scheme.

Don

 

[DonF]

I opened up the power supply and traced through the wiring.

In short, using a timer plugged into the wall instead of the outlet provided on the back of the power supply is a bad idea.

Doing so would provide voltage to the internal circuits of the regulator and transformer when the timer is running, but the head could not operate since power would NOT be sent to the head for the fan and the lamp turn-on relay. This could create a potentially hazardous situation, although the lamp cover interlock would still kill power if the timer were operating and the timer running.

Not recommended!!!!

See this discussion for some details on the power supply voltages and wiring:

https://www.photrio.com/forum/threa...ro-power-supply-troubleshooting.142337/page-2

Best,

Don