Author Topic: DA is dead in my 75 Compact  (Read 1296 times)

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Offline briang2ad

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DA is dead in my 75 Compact
« on: March 18, 2023, 06:38:19 PM »
Years ago I took my 75B compact apart and polished up the trigger bar nicely per instructions here. 

The DA would not reliably work - you'd reach a point at the rear and sometimes the hammer would not release.  Annoying.  So... recently I replaced the TB with a new one thinking maybe I polished a little too much and its worse.  I tweaked the tension on the TBS and even replaced the TB spring with a new one, and still cannot make it complete a DA cycle - ever.  Worse and worse. 

The TBS seems to have plenty of tension and it rides in the grooves nicely and I made sure it is not off center in the frame hole.


Any tips?  Thanks. 

Offline tdogg

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Re: DA is dead in my 75 Compact
« Reply #1 on: March 19, 2023, 01:38:12 AM »
So is it still not completing the DA cycle or is it doing something different with the new triggerbar? 

When it doesn't release in DA, does the hammer spring force the trigger forward to the resting position for DA?  Does it drop to half cock?  Does it revert to SA (does the hammer stay cocked)?

Did you touch the Disconnector at all during your polishing?

How much material did you remove when polishing?  You must have been fairly agressive as it altered the timing.  A little goes a long way in smithin, the surfaces don't need to be mirror.

Cheers,
Toby
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Offline briang2ad

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Re: DA is dead in my 75 Compact
« Reply #2 on: March 21, 2023, 07:10:55 AM »
I don't remember polishing the disco at all.  I extensively polished the TB, but tried not to remove too much.  This is why I als tried another brand new TB with VERY minor polishing. 

I tweaked the TBS - maybe too much pressure now - but it SHOULD work. 

I just have no idea.  Fortunately, I picked up a PCR lower from Stuart here and its now being used as a PCR. 

Offline briang2ad

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Re: DA is dead in my 75 Compact
« Reply #3 on: March 25, 2023, 02:01:15 PM »
Spent time today on the frame.  I ended up putting in a new TRS again, and then changed BACK to the old TB, and now it works. 

Moral of the story:  If you have a dead DA AFTER you've done some work on a 75, it is likely a worn TBS - they can get out of whack pretty easily.  This is my second time on this problem. 

Offline crc4

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Re: DA is dead in my 75 Compact
« Reply #4 on: March 25, 2023, 02:34:12 PM »
An out-of-whack TBS can cause lots of problems. With the angle of the short L, it's easy to not get it installed as deep in that tiny hole as it should be.