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 Post subject: Urei 1176LN rev "F"
PostPosted: Jan Sun 03, 2010 5:34 am 
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Joined: May Wed 27, 2009 8:19 pm
Posts: 236
Location: Flint, MI
I was given one of these units by a radio engineer for Christmas. It needs some help.

There were two 1829 lamps (70mA) in the meter light circuit instead of the 1819 lamps (30mA). Needless to say, it wasn't happy. It opened the 3W resistor and evidently shorted the large 1N2989A zener diode. I see in the revision "G" they replaced the zener with an 7824 regulator. I'm considering upgrading mine to that as well.

Anyways, I was wondering if anyone knows a cross-reference for the "UREI 13-0027" FET? Not sure if it's bad yet, but it would be nice to find a couple just to have them.


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 Post subject:
PostPosted: Jan Wed 06, 2010 6:10 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 2617
Location: Burbank, CA USA
This unit happens to be one of my specialties and we work on them most every day in my shop. I used to work for the recording studio branch of URC back in the late 70's.

You have a valuable unit there and a lot of people would be glad to buy it from you, me included. :wink: The F series is more desirable and valuable than the G series and you should keep it as original as possible.

It uses 2 FET's. Q1 is for audio gain reduction and it can be replaced with a J110 FET. Q11 is for meter gain reduction and can be replaced with a J202 FET.

The 1N2989A is available, though a little hard to find. There's often heat damage where it connects to the PCB so be sure to clean everything up nicely. The lamps are "before" the zener and power resistor in the power supply, so a lamp fault would not damage the those parts, but they do fail sometimes.

Be sure to replace the power supply caps too.

Check out my web site for lots of info about UREI and the URC companies. BTW we have all the 1176LN parts in stock and I'll give you the ARF good guy discount if you email me.

Best wishes...David


Last edited by David Kulka on Jan Wed 06, 2010 7:31 am, edited 2 times in total.

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 Post subject:
PostPosted: Jan Wed 06, 2010 6:30 am 
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Joined: Dec Sun 03, 2006 8:16 pm
Posts: 1252
Location: Pittsburgh PA
David, were you the guy who did the mass purchase of the older LA2/3 T4 modules?

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 Post subject:
PostPosted: Jan Wed 06, 2010 6:44 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 2617
Location: Burbank, CA USA
There were 2 or 3 people that bought large lots when they went on sale and yep, I was one of them.


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 Post subject:
PostPosted: Jan Wed 06, 2010 6:16 pm 
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Joined: May Wed 27, 2009 8:19 pm
Posts: 236
Location: Flint, MI
Hi David!

I'm well aware of the value of this unit. I've always loved the way Urei limiters sound. Even at high levels of gain reduction, they didn't pump or ripsaw

Ironically, I used to own one just like it back in the 80's. I bought it from Audio Distributors as a floor demo for - get this - a whopping $75!! I used it for a few years, and a radio engineer buddy of mine needed something as a backup for his AM, so I let him have it for $65. I've been kicking myself ever since. I've been wanting another one ever since, but the price they command... well, let's just say I can understand why people are building those G1176 kits!

The power caps are first on my list as they're factory. That makes them vintage 1974-ish. I might have to look you up for parts when I get some money.

Thus far, I know the large resistor on the +30v rail is open, and the zener appears to be shorted. The -10v side seems to be within spec. Odd thing is, you can see where this resistor overheated before, but this one looks like new. But it's as open as the clear blue sky. I haven't checked much beyond the power supply, so I don't know if it's demise took out anything else in the unit.


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 Post subject:
PostPosted: Jan Wed 13, 2010 8:44 pm 
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Joined: May Wed 27, 2009 8:19 pm
Posts: 236
Location: Flint, MI
I decided to dig into the power supply a bit more today. I'm happy to say that it's working and tweaked up now. :D

The big zener was fine. C23 just before it was shorted. I replaced the cap and the resistor and had +30v on the mark. I need to get a 3W resistor in there (all I had handy was a 2W) and I probably should change out the other electrolytics, at least in the power supply, if not all of them.

But at least it's working now and it sounds clean.


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 Post subject:
PostPosted: Jan Thu 14, 2010 12:58 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 5429
Location: Upstate NY, USA
Those Urei's were nice units. I used a pair of Urei limiters in the front end of my concert system (late 70's/early 80s). They did a great job. No one could tell when they were working. Thanks to them, the front end even survived a stint with the Ramones.

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http://www.StevenJohnson.com Supreme Instruments 1926-1956


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