sundance-communications.com/forum Forums Other TDM Phone Systems 1A2 and Comkey Telephones & Systems dim lamps

Hi all,

I got my system up and running, will be posting photos soon... I notice on 2 phones that some of the lamps are dim and others are brighter. I was wondering, are they dim do to age or are their different lamps?


Also would any one have extra bulbs and about 2 to 4 24c flat fuses for sale?


Thanks Brian

51a lamps, 10 volt.
52a lamps, 24 volt.

Perhaps you have a combination?

I think Northern Electric might still make the fuses and Sylvania for the lamps.

Someone with better memory will probably correct me.

Depending on the type of set, you could have he L & LG leads reversed. What’s the configuration?

Sam

Thanks Sam and Dean,

I will check the L & LG leads. If I remember correctly from the booklet that I have each lamp does have a L & LG its own leads and not just one for the whole phone.

If it turns out that its the lamps being 10 volt lamps, would any one have the 52a lamps, 24 volt and about 2 to 4 24c flat fuses for sale?

Another question, when you swap out cards. Do you guys recommend to turn the system off? Thats what I been doing as I did not know if it was safe to change cards while the system is on. Then the other hand you have to worry about doing so many power cycles since the the components 40 + years old.

Thanks Brian

When I was servicing 1A2's for the Federal Government it was best NOT to turn the system off (in their opinion).

• You can do Hot Swapping as long as you have extra fuses for the times you pop one.
• If the system is just for your own fun and you are low of fuses...

Remember, it doesn't take all that long for a electro-mechanical system to reboot.

Hot swap or how it is called in professional IT equipment? When I look on WE 400-series line cards developed back in 1950s and on the modern computers - ai say all these PCI cards are not so far from WE 1A2 concept of modular plug&plag concept. So this is where it al started - in Bell Labs.
I also have some difference in brightness of lamps on some telephone sets. I accounted it first to the lamps, but after trying to replace some with brand new ones I saw no difference. So it is most probably a parasite resistance somewhere in contacts, screws or lamp sockets themselves. No solution for that so far.