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All, it seems a few people are sourcing different devices… So far I have seen the following listed in different posts… 74A245 74ACT245 74AHCT245 74HCT245 Just mindful that hopefully there are not

Perhaps make a dual footprint so either will fit, as long as they have the same pin pitch! [email protected]> wrote:

Hi Robin, Opened up my 3400 which has a 1218A prefix and has Q1 and Q2 both as 1850-0038 (date codes 1975 and 1976). My manual which covers much older prefixes, 401 with backdating for earlier 3400A's

Legends / annunciators are a special problem.? Don't know if your particular physical arrangement is covered, but this application note, which was originally HP AN-1012, has some vendor data

Harvey Since I ordered quite a large number of the 74AHCT245 i think its better to change the PCB design accordingly. Just more wasted time but no additional cost. Maciej

Dave 74ACT245s? is what I ordered in SO20W. Already changed the layout to the S020W. Maciej

Thanks Wally, the application note has a lot of interesting detail. To others that have replied, I may not have best described the issue. The RED filter on the instrument is not the issue. The filter

Yves, thank you. I'll try to perform a calibration. Augusto

Some design considerations for contrast enhancement filters are covered in HP Application Note 1015, including suppliers and specific filter models then available in Nov1982:

The two big names in lighting gell filters are Lee and Rosco. Both sell sample booklets so you can find the best colour for you application or do a small display. Seach for a local theater supply or

How about the 'gels' used for stage lighting? They are thin color filters in the form oof a film. Is there a local community theater or a supply house in your area? A full gel would do hundreds of

You mentioned that the frequency was in error by 200 kHz; that is a big error. I suggest the first thing to check is the frequency of the internal reference. Hook a counter to the reference out socket

A number of HP instruments during the1970's with LED displays had a RED filter on the front panel. On the inside surface of these filters there was some sort of photochromic tape which is opaque to

You can find here my experience with 410C. http://www.k100.biz/ebooks/hp_72.pdf If you have something to add and you want to waste a little time, you’re welcome! Yours Gianni

Hello All! I found an HP 70311A clock generator module in my pile here and dismantled it out? to see what was inside.? I dont feel like putting it back together. It is a 70K module, looks like it

Amazing! Youtube Mr. Carlson has a similar video with a bit more engineered solution than CuriousMark - no idea if it's "better" or not from a performance standpoint.? Complete replacement chopper

I've done that, would it be reasonable to order the 74LS245's instead? Harvey

I'm pretty sure I have a large number of 74ACT245s in SO20W packages, if that would be helpful. I may have others as well; I can check. -Dave -- Dave McGuire, AK4HZ New Kensington, PA

Got my? parts today and I can believe it but I ordered the wrong version of the 74LS245 SOIC packages.?? I will need to change the board again.? Manufacturers went crazy with SOIC standard.

Hello, Am I a glutton for punishment, or what?? Having completed my restoration of a 410B, I happened on a fairly rough 410C at the flea market for $15.? Seller said it worked.?? Actually, not