5 replies to this topic

[Finger Prints]

This came with the '63 Edmund Scientific 6" F8 Newtonian telescope I obtained not too long ago.
I've done an Internet search for the company name, the model number, etc. The company's address is/was in Batavia, Illinois. The owner may have been Bruce (?) Vogel.

Does anyone have any information about this item?

Initially, it presented with some fractured PC-board solder-joints associated with the speed-control (slider-type variable resistor) in addition to the typical fouling of the sliding contact surfaces. Reflowing the solder on those defective joints and cleaning the contact surfaces has apparently restored the unit to good working order.

The rub is that the plug-in the wall powerpack gets hot enough to start emitting the toasting-plastic smell along with alarmingly warm areas of its case over the course of perhaps five minutes. Both suggesting it's overloaded. All the while, the controller appears to function correctly with the Tracking Indicator light increasing/reducing its flash-rate when altering the controller's speed-control.


With an input of 120vac at a maximum of 0.25amps, the power-pack is rated for an output of 12vdc at 0.25amps (MAX of 12w).

- The telescope's tracking-motor is the original OEM unit that came with the ES equatorial-mount. The motor itself, made by Cramer Controls Corporation in '63, is rated for a maximum full load of 2.7w at 115vac. It works correctly just plugged into a 110-120vac wall-outlet albeit running a bit slow hence, the Vogel unit
- Powering it with 123.6vac, the power-pack presents with 11.4vdc with no load (that may be an indicator of pending doom in itself) and does not get warm to the touch.

I've not put an amp-meter to the output side of the thing just yet (as it's a DC current, I'll need to place my DVOM in-line with the circuit to measure the current).

My brother, whom I got the heap from isn't 100% sure that this particular power-pack originally came with the Vogel unit.

I don't know what the functioning controller's expected 12vdc power demand is.

The voices in my head all agree that the power-pack is overloaded. I'm considering just replacing the power-pack with one of a higher capacity.


Anyone have any factual information?

Thanks for any input.

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[andylsun]

Any pictures of the inside of the VE minitrack? I just tore apart a home made variable speed drive for my parks optical.

[Finger Prints]

Any pictures of the inside of the VE minitrack? I just tore apart a home made variable speed drive for my parks optical.

A couple of integrated circuits (ICs), a couple of SCRs, a reference crystal and output transformer along with the associated supporting components. Not a whole lot to it.

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Edited by Finger Prints, 02 October 2024 - 04:38 PM.

[andylsun]

Cool!  Not a huge jump from home made!

[deSitter]

Cool!  Not a huge jump from home made!

A fork is a fork Ah the days when electronics were simple!

 

-drl

[DAVIDG]

 Have you measured the output voltage and frequency ?  The basic design is it takes 12 volts dc and pulses it into the secondary of the transformer and that kicks it up to 120 VAC ( about 150 volts peak to peak). The frequency is set by the frequency that secondary is pulsed at.  That is what the timing circuit is doing based on crystal to have stable output.

   The common failure mode is  one of the transistors or SCR that feeds the secondary on the transformer is bad and will fail closed so it is  dumping current into secondary all the time. When it is working correctly it shouldn't pull more than 1 amp. 

 

            - Dave