GE 3-6025A transformer

[valbg]

Hello all fans,
I own a GE 3-6025A. I want to use it in Europe, i.e. 230 volts supply voltage. Unfortunately, its original (120V) transformer is missing. I have a service diagram (I am attaching only the power board cut out), I also have a photo from the Internet of the inscriptions on the transformer.
Please, if anyone owns this retro jewel, measure the voltages of the two secondary windings for me, so that I can choose a suitable transformer.
Thank you in advance for your attention.
Warm greetings, Valentin.

 

[hopey]

I love these threads, Just use an old Laptop power supply it has good voltage regulation and high power output. You can go a little higher on the DC voltage. but not lower. This will improve the sound output as apposed to the internal transformer and they are free.

 

[Superduper]

Pay no attention to Hopey, he tenders useless gibberish, often dangerous advice. I sometimes suspects he purposely posts these to undermine the forum. One careful look at the schematic and one can see that this circuit expects 9V for the main rail, and the transformer has an additional small winding to power a 3v circuit. No 19V laptop supply will have dual secondaries and if you inject 19V into the boombox when it’s expecting 9V, suffice to say following that advice could result in catastrophic results.

 

[Superduper]

Here’s some advice for you that you might find a bit more useful. This transformer has 2 secondary winding. One for the main circuit and a smaller one probably for the clock circuit. The main power supply should provide about 9VDC. The smaller winding powers a 3V circuit. You’ll also need to study the power supply which for the main circuit includes a capacitor filtered full bridge rectifier. These types of circuits typically boosts the AC secondary to approximately 1.44x when rectified and filters to DC. Based on that, the most common secondary voltage choice will be 6.3V. You can install it and check the PS output between P2 and P3, I believe you’ll find approximately 9V there when a 6.3v secondary transformer is used. As for the other winding, that circuit does not have a full rectifier bridge or the large capacitor so it’s likely a 3V secondary. Furthermore, unlike the main circuit, this one is unswitched so it’s on whenever it’s plugged in. It’s likely a custom winding and you are unlikely to find an off the shelf with dual windings with that kind of voltage split. I suggest you either get a second smaller separate transformer (which can be tiny because I do believe this circuit uses minimal power). Or you can custom modify your power supply to tap an additional rail and drop down its voltage to supply that 2nd circuit.

 

[valbg]

I considered the option with a switching power supply followed by an LDO regulator, but this, besides being more expensive, will take up the only "free" space - the battery socket and, although not the most important, it will not be a vintage restoration.
A 6.3VAC transformer is less common and accordingly more expensive. I ordered a 6.0VAC/1A, which, although a little difficult, will be installed in the place of the original one, and with which I want to check what happens.
As for the second 3VDC power supply - it is used for the PLL module/memory of the stations (in parallel with 2 AA alkaline batteries) and in the circuit of related models of radio cassette players it is even missing (batteries will be changed more often) or maybe I will try to provide it from the main 9V with a step-down.
I will gladly accept other advice/recommendations, and when I get results I will describe them here.

 

[Superduper]

Yes that will be my recommendation. Although I am puzzled by your comment on difficulty in finding 6.3v transformer. It’s very common here. Just like 12.6V transformer is common. Maybe look a bit deeper. Since you already have a 3v battery backup, that second winding is not a big loss, especially if you use the eveready lithium 1.5v AA cells (which I presume is what are used). They last much longer than regular alkaline cells. You can also locate small 3v power supplies fairly cheaply. Source the AC power directly from the same location your 6V transformer gets its power from. If space is an issue, you can probably also eliminate the plastic shell as well. As for cost, that’s for you to decide. As for original restoration, if that’s what you want, you’ll have to find a used unit to cannibalize for parts, as that transformer is almost certainly custom wound and sourced for that particular application, it’s going to be virtually impossible to find a new off the shelf part with those exact same specs.

 

[valbg]

Yes that will be my recommendation. Although I am puzzled by your comment on difficulty in finding 6.3v transformer. It’s very common here. Just like 12.6V transformer is common. Maybe look a bit deeper. Since you already have a 3v battery backup, that second winding is not a big loss, especially if you use the eveready lithium 1.5v AA cells (which I presume is what are used). They last much longer than regular alkaline cells. You can also locate small 3v power supplies fairly cheaply. Source the AC power directly from the same location your 6V transformer gets its power from. If space is an issue, you can probably also eliminate the plastic shell as well. As for cost, that’s for you to decide. As for original restoration, if that’s what you want, you’ll have to find a used unit to cannibalize for parts, as that transformer is almost certainly custom wound and sourced for that particular application, it’s going to be virtually impossible to find a new off the shelf part with those exact same specs.
View attachment 61630

I mentioned at the beginning that I want to use GE in Europe (230V). And specifically in Bulgaria no one offers a 6.3VAC secondary winding. I will try tomorrow with 6V and if it turns out to be insufficient, I will look for a second-hand one or another solution.

 

[Eddy]

Hello all fans,
I own a GE 3-6025A. I want to use it in Europe, i.e. 230 volts supply voltage. Unfortunately, its original (120V) transformer is missing. I have a service diagram (I am attaching only the power board cut out), I also have a photo from the Internet of the inscriptions on the transformer.
Please, if anyone owns this retro jewel, measure the voltages of the two secondary windings for me, so that I can choose a suitable transformer.
Thank you in advance for your attention.
Warm greetings, Valentin.

Was searching the web regarding this box . No AKA's found as they had a version of the GF9797.
Kinda like this box because of the digital tuner , separate bas - treble .

 

[Eddy]

I considered the option with a switching power supply followed by an LDO regulator, but this, besides being more expensive, will take up the only "free" space - the battery socket and, although not the most important, it will not be a vintage restoration.
A 6.3VAC transformer is less common and accordingly more expensive. I ordered a 6.0VAC/1A, which, although a little difficult, will be installed in the place of the original one, and with which I want to check what happens.
As for the second 3VDC power supply - it is used for the PLL module/memory of the stations (in parallel with 2 AA alkaline batteries) and in the circuit of related models of radio cassette players it is even missing (batteries will be changed more often) or maybe I will try to provide it from the main 9V with a step-down.
I will gladly accept other advice/recommendations, and when I get results I will describe them here.

I remember having a problem with a Sharp GF9595 , that PLL tuner only works when the AA 's are installed.So not only for clock ,memory storage
In mine the DC DC converter was shot , so it did not work with fresh AA's in it
Don't know if the GE works the same way

 

[valbg]

Yes that will be my recommendation. Although I am puzzled by your comment on difficulty in finding 6.3v transformer. It’s very common here. Just like 12.6V transformer is common. Maybe look a bit deeper. Since you already have a 3v battery backup, that second winding is not a big loss, especially if you use the eveready lithium 1.5v AA cells (which I presume is what are used). They last much longer than regular alkaline cells. You can also locate small 3v power supplies fairly cheaply. Source the AC power directly from the same location your 6V transformer gets its power from. If space is an issue, you can probably also eliminate the plastic shell as well. As for cost, that’s for you to decide. As for original restoration, if that’s what you want, you’ll have to find a used unit to cannibalize for parts, as that transformer is almost certainly custom wound and sourced for that particular application, it’s going to be virtually impossible to find a new off the shelf part with those exact same specs.
View attachment 61630

I mentioned at the beginning that I want to use GE in Europe (230V). And specifically in Bulgaria no one offers a 6.3VAC secondary winding. I will try tomorrow with 6V and if it turns out to be insufficient, I will look for a second-hand one or another solution.

Was searching the web regarding this box . No AKA's found as they had a version of the GF9797.
Kinda like this box because of the digital tuner , separate bas - treble .

GE has 4 models from the Model 3 series with "Electronic Tuning System" 6015 (mono), 6025 (which I am trying to change and I don't know if there is one with another brand).
There is also a 6035 which is identical to the Loewe RS-2000 and the only difference between them is the power adapter, and that the European one simply relies only on 3 volt batteries (it lacks a 3V mains power supply).
The last one (which I have found) is the 6045 with a European version of the Telefunken HP-1800 (or just 800) - a very good functional and musical machine.

 

[Eddy]

I own a HP 800 , did not know of the GE AKA .
A Loewe is still on my wishlist but it's a shame you cannot use one as a donor for its power supply