Dynalogic Hyperion with gooey potted transformer

[dadscomputerlab]

I have a Dynalogic Hyperion that has a flyback transformer with potting that is a caramel-like consistency at room temperature. The goo already leaked onto other components that I'll have to clean. I haven't powered it up (and don't intend to until I do more repairs) but the seller told me that it doesn't boot.

My tentative plan is:
- clear out the old potting material
- check the transformer for damage
- seal it up with new potting

This is a new issue to me. Has anyone dealt with this before? Is this a good course? Are there other things I should be considering?

Thanks!

 

[Hugo Holden]

Occasionally you can see a twin lead EHT cap. Generally it was done to gain access to the EHT terminal for one reason or another, such as to create a divider for a focus chain (more commin in color VDU's) or to add some additional filter capacitance to the EHT when the CRT's bulb capacitance was inadequte. The EHT rectifier is potted inside the flyback transformer. so Only DC is presented to the cap via the white wire.

If there where more photos I could tell better, for example if the grey plastic rectangular box is a blind box, with no wires entering it except the big red one from the EHT cap, then really the whole tub of goo is simply a way of insulating the cut end of that extra wires so that it does not arc over to anything else. If that is the case, I'd discard it and fit a new single wire EHT cap. But if there is a wire exiting the base of that rectangular chamber or some external connection to it, it may have another application such as a HV filter cap.

 

[channelmaniac]

If there where more photos I could tell better, for example if the grey plastic rectangular box is a blind box, with no wires entering it except the big red one from the EHT cap, then really the whole tub of goo is simply a way of insulating the cut end of that extra wires so that it does not arc over to anything else. If that is the case, I'd discard it and fit a new single wire EHT cap. But if there is a wire exiting the base of that rectangular chamber or some external connection to it, it may have another application such as a HV filter cap.

there could also be a multiplier inside the potting.

On Roland synths the red epoxy under the keys turns gooey and spreads sticky mess everywhere as it sags and drips. It can be removed using lye and water, making me wonder if the epoxy used on that flyback could be dissolved that way.

One HUGE possible downside is damaging the coating on the wires inside that flyback.

 

[Hugo Holden]

there could also be a multiplier inside the potting.

I doubt that, the EHT wire comes out of the overwind assembly on the flyback transformer and to the CRT's anode cap. The red wire from there passes to the goo filled container. If it were a multiplier the EHT wire would likely pass to that chamber first, then another wire would exit it to the EHT cap. Though as I mentioned, we need more detailed photos to see if any wires exit the goo filled chamber, or it is mainly guesswork. We often get presented with questions where too little detail is provided, making our crystal balls go hazy.