Lexicon 300 Display Transformer needed

[la-2a]

Hello folks, can someone tell me where I can get this transformer.?? Lexicon 300 PSU, Display Transformer 470-07509.
Thanky you very much...

 

[la-2a]

Does anyone know of a replacement solution if the transformer is no longer available for purchase?? Can anyone explain the connections J20, J21 FILA FILB.??

 

[radardoug]

Fila,b are on the display, it has a filament to heat it.

 

[la-2a]

Ahh. O.K. Is this AC ? How many volts?

 

[radardoug]

Yes of course its ac, it comes off a transformer. Unfortunately Lexicon didn't put the voltage on the drawing, so the only way to find it is measuring it or look up the display data sheet.

 

[la-2a]

It looks like it will hardly be possible to find such a transformer. So I have to build something adequate. Can somebody help me with it. ?? There would be enough space in the housing. I think we would help a lot of Lexicon M300 users out there!

 

[Crash]

Has anyone reached out to Lexicon to see if they might be of help? I bought a replacement for my cooked transformer years ago, but I can't remember where. I thought I got it off of Digikey or Mouser but it's all foggy now. I am still searching to see if I can find any evidence of what I did back in the day, but I may be grasping at straws at this point.

 

[la-2a]

Hi, I contacted Lexicon / Harman, no Transformers in stock anymore...the Manufacturer was Lenco Electronics.They don't have any in stock either. The unfriendly gentleman at Lenco didn't even want to reveal the voltage pin assignment of the transformer without an authorisation. Is somebody here to give the correct values.??

 

[Crash]

I wish I could remember where I bought mine, it very well could have been from Lexicon or Lenco. It's been many years back.

 

[Crash]

I don't see why Lenco wouldn't build one for you since they seem to build custom transformers. They say low cost samples right there on their website. I am sure it gets weird with it being probably a proprietary unit that Lexicon had them build but it might be worth a shot.

 

[Crash]

Looking at my original posts, they seem to be early 2014, no wonder I don't remember much.

 

[MS-TAS]

I did one of these recently. The filament likes about 3.3VAC, ideally center tap as shown.
Other windings were 35VAC

 

[Memo Solis]

Hi we have one unit scape, please take a picture for check it

 

[la-2a]

Hi we have one unit scape, please take a picture for check it

Hello, you can see the photo in my first post.. thank you

 

[la-2a]

Hi, I solved the problem. I used two small 2VA AC transformers that I soldered onto a small breadboard with 2.54mm pin headers at the location of the broken transformer. 230V/2x18V 2VA, 230V /2x6V 2VA. The 230V: 2x18V only were soldered directly behind the mains fuse on the primary side, because there´s only 120V on the PSU board, which was just right for the 2x6V transformer to generate the 2x 2.5V filament voltage. Please pay attention to your country-specific mains voltage in order to select the correct transformers.

 

[mumek]

Hi, I solved the problem. I used two small 2VA AC transformers that I soldered onto a small breadboard with 2.54mm pin headers at the location of the broken transformer. 230V/2x18V 2VA, 230V /2x6V 2VA. The 230V: 2x18V only were soldered directly behind the mains fuse on the primary side, because there´s only 120V on the PSU board, which was just right for the 2x6V transformer to generate the 2x 2.5V filament voltage. Please pay attention to your country-specific mains voltage in order to select the correct transformers.

Hey, I'm trying to solve the same problem with my own 300. How did you find the right transformers for the job? Do you have a link or part number?

 

[mumek]

Nevermind, I figured it out! If anyone in the future is trying to resurrect the dead display of a Lexicon 300, and sees this thread, message me! I can help you.

 

[DoctorQ]

Hi mumek I am having a similar problem my 300's display show up while powering on the device but after 10 secondo it goes off. How did you figure it out?

 

[mumek]

So, I’m a gear tech by trade. I fix electronic music machines for a living. With Lex 300’s, there’s a custom transformer driving the display voltage. The display is a special type that takes a high DC voltage and a low AC voltage, 35VDC and around 3VAC. The custom transformer was made to provide these voltages, and they aren’t made anymore and there’s no longer a way to buy old stock. Over time, as the power supply parts wander outta spec with use, the voltages stray and tax certain components. With the display driver transformer’s circuit, there’s a capacitor that literally flames out. When it goes, it creates a short in the transformer circuit that takes out the 35v winding. This transformer roasts itself to death, and your Lex300 goes dark. The transformer in mine crumbled to dust as I removed it. To replace it, I had to wire two other transformers together on a turret board, and the voltage they provide still isn’t perfect so the display is a tad dim. If you haven’t had the power supply capacitors replaced yet, unplug your 300 immediately. If you’re adept with a soldering iron & desoldering pump and versed in electronics, you can replace the capacitors yourself, but otherwise, bring it to a tech. It may not be too late, you may be able to save your display transformer, but you cannot keep using it as is.

 

[Disco Volante]

It would be reasonably simple to wind a new transformer, I guess?