DIY Audio Projects Forum

Hi Everyone, I have had this radio for a while and am trying to see if it can be revived. The wiring is horrible, but intact, the tuning cap needs repair and worse...the electronic guts are encapsulated in a single chunk. Does anyone have a schematic for it? The link shows the model. Mine has C.Brandes inc phones as well.

https://www.radiomuseum.org/r/insuline_ ... _110v.html

Good listening
Bruce

_________________
Some of my DIY Tube Amplifier Projects:

• PoddWatt: 5751 / EL84 Push-Pull DIY Tube Amplifier Project
• OddBlocks: KT88 Push-Pull DIY Tube Amplifiers (Mono Blocks)
• ForeWatt: ECC802S (12AU7 / ECC82) DIY Tube Preamplifier Project
• GrooveWatt: Tube (Valve) RIAA Phono Preamplifier Project

Bruce if you go to the bottom of the page you included as ref. At the bottom you see 2 pics one of the ICA symbol and the second
looks like a pile of papers. If you click on the papers the page it takes one to pic which when hovering the mouse says if you join you can get sch's of models they have.
Have you tried this avenue?
Another way is to check for really old stuff, if it was registered for copyright/patient.
A request with the proper model# etc to the USA patient office may be worth a try if all else fails.

Hi, Thanks for the thought on the patent idea. Maybe. I checked on the other link and no schematic. Not in "Riders" either nor at the company web site. It isn't even listed as one they made. I'm guessing it was a really low production thing and eveyone has forgotten about it. I have started to map out the active part of the circuit. The PS is fully encapsulated in a type of plastic, probably like bakelite and is inside a metal case that is welded to the chassis. It is not likely to be functional and I would not trust it anyhow. The restoration will be somewhat more modern and eliminate a potential shock hazard as one side of the headphones goes to the sub chassis via a 10K resistor. The sub chassis is connected to the AC mains even though there is a power trannie in use. I guess they didn't see that as a hazard if the resistor failed. I have seen some designs like it that routed the B+ through the headphones as well. Ugh!

Still searching

Good listening
Bruce

_________________
Some of my DIY Tube Amplifier Projects:

• PoddWatt: 5751 / EL84 Push-Pull DIY Tube Amplifier Project
• OddBlocks: KT88 Push-Pull DIY Tube Amplifiers (Mono Blocks)
• ForeWatt: ECC802S (12AU7 / ECC82) DIY Tube Preamplifier Project
• GrooveWatt: Tube (Valve) RIAA Phono Preamplifier Project

Hi Everyone, I posted this on another forum as well as here because I asked there for assistance as well.

After dissembling the radio I have come to a few conclusions. First this thing is dangerous to use. Back in the era of knob and tube AC mains it might have made sense. Now it is a serious no go. The tubes are powered by a dual winding 2.5 volt secondary. The high voltage is taken from the AC mains directly (ouch). Much worse when you discover that the phones are only isolated from the AC mains by a resistor. If it fails and the polarity is wrong you hear music of the angels and not the local AM station. BTW no fuse either and only one side of the AC is switched. Now to other details. The filter capacitors inside the Bakelite mass are toast. The B+ is created from the AC mains with one of the type 227 tubes used as a rectifier. Crude to the max. The wiring is toast and the coil is damaged. So I am not going to refurbish this thing. I’ll keep it as it is interesting, but there is no real way to make it safe and useful without a complete rebuild.

Good listening
Bruce

_________________
Some of my DIY Tube Amplifier Projects:

• PoddWatt: 5751 / EL84 Push-Pull DIY Tube Amplifier Project
• OddBlocks: KT88 Push-Pull DIY Tube Amplifiers (Mono Blocks)
• ForeWatt: ECC802S (12AU7 / ECC82) DIY Tube Preamplifier Project
• GrooveWatt: Tube (Valve) RIAA Phono Preamplifier Project

Just the thought of putting ones fingers on that 120v ac plug is a scary thought.
Plugging them in is not bad but unplugging one and not slipping a finger onto a
prong takes focus. I have changed many of those on lamps and heaters. Scary scary.