EUa2 Repair.

[hcs]

After a long time with no restoration, I decided to restore my EUa2 umformer.
The reason was that I just got this U10a1 umformer and I then wanted to test my Ukw.E.e and 10W.S.c with their umformers.
I knew from before that the capacitor block (cap. 2, 3, 4) was bad(expanded), so I replaced them inside the can. I have done no further repairs to the EUa2. I have tested the 130V with a 5Kohm load to check the voltage with load.
With 12V in, I have 130V out from the EUa2, the outpuc fluctuates around +- 1V. I did measure 229 mV AC noise, at the 130V output, with 5Kohm load.
I can hear changes in the speed of the umformer motor, which correspond to the fluctuations of the output. Is this performance what is to be expected?
Would you recomend to clean and regrease the bearings?
I guess cleaning of the carbon brushes and commutator, should be done.
Hope to get some advise.

[Dufleuve]

Hello,

Cleaning the mobile parts (bearings, brushes, collector) and greasing the bearings is the first thing to do.
Up to now, has been enough for most of my EUa.

Cheers

[Funksammler]

Cleaning the bearings can't do much harm, although if they are not noisy they are not a real problem. you can easily lift out the motor-generator out and gain access from the sides. First however I would clean the commutator and check that it not too rutted. A bit of emerald paper and some contact spray should do the trick. The irregular running is probably due to a dirty commutator. If you look closely, you will probably see some sparking in time with the variations in running. Also check the caps on the motor generator, but usually these are OK. After cleaning, let the umformer run for an hour or so to give it a chance to build a nice patina. The more it runs, the better it gets!

regards,

Funksammler

[Tornfuté]

Hello i have clean a lot of them , first i put my last finger and try to
rotate the rotor , sometimes it ´s fix , i proceed like this
At first remove all brushes , then open seu by unscrewing both sides
remove rotor , clean inside of inductors with sandpaper , sometimes
It's hard rusted .
Then like already written , degrease bearings with alcool , clean
rotor , put new bearings grease , don't fasten all screws at first
try again if rotor is now free of movements , fasten everything
Let it work, eventually , turn the brush holder to adapt voltage output .
Like said it takes at first around 5-6 A then decreasing to around 2,3A
i have some seen running but it was not 2,3 but around 3A , don't know why
short circuit in rotor ?
Pierre

[Val]

Hello i have clean a lot of them , first i put my last finger

If this is your last finger you have been cleaning those umformers 9 so far to be exact

ps. sorry about that little joke - i know that English is not your native language, however i couldn't resist it - joke was too good. please don't offend

[Tornfuté]

Val no problems for the joke , i still have all the fingers
Pierre

[me6_130]

If this is your last finger you have been cleaning those umformers 9 so far to be exact

ps. sorry about that little joke - i know that English is not your native language, however i couldn't resist it - joke was too good. please don't offend

That was good.

I'll also take note of procedures...for when I need to clean mine.


Carles