74175 vs. 74LS175 | Museum of the Game® & International …
2012年8月30日 · For a Gottlieb driver board - quickie math says the 74LS175 is fine. Each output from 74175 drives one transistor - either MPSU45 or MPSA13 Max current load from an MPSU45 transistor is 2 amps and is the higher load of the two transistors. Minimum current gain from U45 is 25000. Max current required from 74175 = approx 2/25000 = 80uA
74LS174 or 74LS175 for 74LS74? | Museum of the Game®
2014年1月14日 · Okay, I will answer the why first. I just received an order of ICs and somehow I ordered everything except this IC. I hate to wait another week or two for one chip. I know that the 74 is a dual d-type flip flop, while the 174 is a hex d-type flip …
gottlieb system 80 driver board 74ls175 transistor/coil locking on.
2009年12月25日 · gottlieb system 80 driver board 74ls175 transistor/coil locking on. Using my hh to get this other machines boards right. Boots up fine, mpu/cpu good by swap. Driver board. Ok at first but once you start a game the lower playfield lamps turn on, and the lower pf up kicker relay turns on and both stay on. The problem has been narrowed to the ...
What fixed your game today / general repair log
2017年3月10日 · pulling ht 74ls175 @ n4 so I can at least test the counters, extgernally it's ok both counters seem good put in a new 74ls175 @ n4 now I have sync all outputs of p4 seem correct testing with fluke bus test ok, RAM long 0x0000 - 0x03FF - ok no video roms all 2101's missing, going to put in sockets and replace replaced, game boots,
Flying Shark Bootleg Repair | Museum of the Game®
2017年11月17日 · Hi, I have found some more info out by probing around. The Video Sync is handled by an HD6845SP processor. After some chasing of the output I found that this terminated at a 74LS175 flip flop. Interestingly I have found that the complement input signal to Sync looks like it is floating or very week at least.
Where do you guys buy your 74LSxxx series chips from?
2008年7月21日 · If I need to buy 1 type specifically for a repair and because I don't already have them in stock I typically buy from eBay UK - often Polish or other European sellers have what I want and it's cheaper than the postage from one of the other suppliers.
Tech: WPC Dot Matrix Controller Board Problems
2004年11月10日 · Hi, I hope some one can help me. I have a WPC Dot Matrix Controller Board (A-14039) that I am having problems with. When first powered up, the DMD has garbage all over it and is not blank like when using a good Controller board. When the High scores are shown, the display looks good and...