Build Your Own Arcade Controls Forum

Arcade Collecting => Pinball => Topic started by: RayB on November 11, 2010, 03:22:03 pm

Title: Why are UDN chips so rare when...
Post by: RayB on November 11, 2010, 03:22:03 pm
all these guys make them:

http://www.chinaicmart.com/buyer/search.html?keyword=UDN7180a&searchtype=1&sel1=1 (http://www.chinaicmart.com/buyer/search.html?keyword=UDN7180a&searchtype=1&sel1=1)

Title: Re: Why are UDN chips so rare when...
Post by: Pinball Wizard on November 12, 2010, 02:39:48 pm
What are these chips used in?

If you want to talk about rare chips try and find the original chip for my Say-It-Again board in my Centaur. I gave up and are eventually just going to build a replacement board for it.
Title: Re: Why are UDN chips so rare when...
Post by: RayB on November 12, 2010, 06:56:37 pm
The UDNs control segments in high voltage glass displays like you find in pre DMD as pins.  I learned from someone that though there are companies claiming to make them, they are mostlymcompletely unreliable or don't work at all.
Title: Re: Why are UDN chips so rare when...
Post by: Q*Bert_OP on November 12, 2010, 07:05:12 pm
The UDNs control segments in high voltage glass displays like you find in pre DMD as pins.  I learned from someone that though there are companies claiming to make them, they are mostlymcompletely unreliable or don't work at all.

Correct. These chips are often counterfits, and usually don't work. Same thing with the 6821 PIAs...good luck finding these new.