sundance-communications.com/forum Forums General General Telephone & Systems Information found in the telco closet

i found this MPS2222A transistor hanging on a nail in a telephone room with a 16-cabinet Option switch. it looks like it's been there a while from the yellowed packaging but i want to know what it would've been used for? it looked deliberately placed there...

blue tooth silicon boob maybe

Radio shack sells transistors?

Thats just a basic NPN Xsistor Was there a paging amp near the phone system?

I think they take a bunch of those comopnent thingys and glue them togther and wala a phone system. lol
Very common transistor found in alot of things.

There was a time when telephone repairmen really were expected to repair things. There was probably a system in that building that kept blowing transistors, and a real phone man knew how to troubleshoot, unsolder and solder them. Don't worry, we are a dying breed and won't be around much longer.

Whew, that's a relief. Can you imagine what would happen if that sort of thing were allowed to continue? Everybody knows that the key to a strong, resilient economy is dumpsters overflowing with cheap disposable plastic crap.

Jim
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Speaking from a secure undisclosed location.

In the late '70s I worked for a company that had put the PBX into the Barbizon Hotel for Women in NYC. I got sent there on a repair one day (Very bizarre- only man in the place. Had to be very careful walking on the floors, etc.). Anyway, problem was easy - BDR (Bell doesn't ring). I go upstairs find the phone, have the operator call me and sure enough - BDR. I open the set, put my butt set across T&R to make sure that I've got generator coming out of the switch, call the operator toeing me again, and SOB! The bell rings. Bad condenser on the network. I go down to the switch room to look for spare sets and there are none. I call the office and report that I'm going to have to come back to get a set and the repair foreman says "NY Tel never cleaned up after they disco'd the Interface equipment. Find a capacitor that's about the right size on one of the cards, cut it off and use that."

Which is exactly what I did. Worked like a charm

Sam

That's one of the most ubiquitous transistors made. It was found in just about every amplifier and was also a cheap relay driver.

I had to laugh, Silversam. A lot of the guys here won't remember this. Eons ago, there were devices required by the telco that had to be installed ahead of the "foreign" telephone interconnected systems like PBX and key systems. These devices were called Voice Connecting Arrangements or VCAs. They were also known as "couplers." Most of the WECO units worked. The Pulsecom units were nothing but a load of problems. I remember carrying around an assortment of diodes and small electrolytic capacitors needed to "field repair" the modules. You see, most of the time, there were no spares on site. When the VCA was removed, the customer had no dial tone on that line. So, to keep the customer happy, we regularly repaired the units on site. Tools needed: One Marksman 40 watt iron, one solder sucker and a pair of mini needle nose pliers and a hand full of capacitors. Worked every time.

Rcaman

Sam, the 400D KTU's have at least three capacitors of the proper value, which is .47 mFd. I have often used them for just such a repair. The EB ringer had a nice "official" cap with two pigtail leads, that could be used, too.