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 > Magnetek TU-775-2

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Master6969420

Oregon

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Posted: 10/14/20 06:54pm Link  |  Quote  |  Print  |  Notify Moderator

Hi, i have a 1989 foretravel grand villa motorhome and my Magnetek TU-775-2 charger converter is failing and needs replaced, i found that this particular one was a bad model and would like to know what you would recommend as a replacement

BFL13

Victoria, BC

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Posted: 10/14/20 07:12pm Link  |  Quote  |  Print  |  Notify Moderator

This one?

https://picclick.com/Magnetek-TU-775-2-C........GER-TRIAD-UTRAD-75-AMP-142987792985.html

Was a thread recently about these in older Airstreams. Anyway, in my MH, with a different older converter, I just swapped in a PowerMax deck mount, worked out perfectly. I was able to keep the OEM 120v circuit breaker panel and the DC fuse panel. You could use the 75 amper I guess.

https://www.boatandrvaccessories.com/pro........-amp-12-volt-power-supply-with-led-light


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MEXICOWANDERER

las peñas, michoacan, mexico

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Posted: 10/14/20 08:12pm Link  |  Quote  |  Print  |  Notify Moderator

The 775-2 is a ferroresonant charger that has a fixed output voltage of 14.0 volts. They are not adjustable. I'd love to get my hands on one even though it would need all new capacitors and rectifiers and fan and.....

time2roll

Southern California

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Posted: 10/14/20 08:28pm Link  |  Quote  |  Print  |  Notify Moderator

This will serve you well.

Boondocker $145

Or do you need the entire fuse/breaker/electric panel?

PD MightyMini

If you have 4 or more batteries I might recommend something different.


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Gjac

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Posted: 10/15/20 09:23am Link  |  Quote  |  Print  |  Notify Moderator

How is it failing? Does it overcharge or undercharge your batteries? What is the voltage out put?

MEXICOWANDERER

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Posted: 10/15/20 10:20am Link  |  Quote  |  Print  |  Notify Moderator

Old capacitors short or go open circuit. Unlike most "experts" who do nothing but know everything I actually opened open and repaired old converters. The case of the 775-2 was riveted to the steel chassis. The active elements were a transformer, tuning capacitors, and 4 35 amp rated 100 PIV rectifiers and a 10-amp 250 volt fuse. A two foot 15 amp rated 120vac grounded plug and 18" of stub 6 AWG Aircraft like wire. One red the other white.

rlw999

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Posted: 10/15/20 02:17pm Link  |  Quote  |  Print  |  Notify Moderator

Master6969420 wrote:

Hi, i have a 1989 foretravel grand villa motorhome and my Magnetek TU-775-2 charger converter is failing and needs replaced, i found that this particular one was a bad model and would like to know what you would recommend as a replacement


If it lasted 31 years and hasn't caused any problems until now, it doesn't sound so bad other than it being a single-stage charger.

MEXICOWANDERER

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Posted: 10/16/20 03:44pm Link  |  Quote  |  Print  |  Notify Moderator

Main disappoinment. The higher the voltage the fewer the amps. Ferreresonant is very slow the last 15%

Danged near blowup proof.

Gjac

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Posted: 10/17/20 09:20am Link  |  Quote  |  Print  |  Notify Moderator

MEXICOWANDERER wrote:

Main disappoinment. The higher the voltage the fewer the amps. Ferreresonant is very slow the last 15%

Danged near blowup proof.
My Magnatech 950 converter/charger is 25 years old and still works fine. Many on here called them battery boilers but I never understood how 13.6 v when new and 13.2 v after 25 years can boil your batteries? I notice if use it to top off my batteries for a few days after my "smart charger" says ful I can dry camp couple of days longer. I always wondered if that slower charge for the last 15% was easier on the battery plates thereby increasing the life of the batteries?

MEXICOWANDERER

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Posted: 10/17/20 11:39am Link  |  Quote  |  Print  |  Notify Moderator

These beautiful blocks of brushed aluminum (sheet metal) came out of the factory capacitor tuned for 14.0 volts, They are tuned by 120vac hertz. If a generator is running slow the finish voltage was lower: I.E. 63 Hz = 14.4 finish volts.

I became an OEM for BW Magnatek. But their other products I would not touch. Such as the converters with the bleed resistor.

I modified dozens for customers that used a 6-hour wind up timer. It added a 180 Ohm capacitor that changed the finish voltage to 14.7 volts, This shifted battery voltage upward and radically decreased charging time. For always cold climates I added a 30 amp Shottkey rectifier that permanently added +.30 vdc.

Keep in mind this was 40 years ago.

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