Telefonica Amper Teide (D) classic corded phone repair (solved)

[Chungalin]

This is an classic (1990) corded phone from Spain’s national telecom company Telefónica. It’s a Teide "D" version manufactured by Amper. It’s the first phone I had and I wanted to repair it. It ringed OK, but it didn’t work when I lifted the receiver. All silence.

Receiver switch is OK. I check some MPSA92 and MPSA42 transistors, nothing wrong. But when I check round diode bridge B250C1000, I see it’s not conducting in one way! Replace it with a scrapped one and it’s working again!

[CapLeaker]

Re: Telefonica Amper Teide (D) classic corded phone repair (solved)

Like about 10 months ago, I had some of our phones apart (the spare phones pile was getting low). Those where made by Nortel (Canada) for phone exchanges like a 3x8 or 4x16 etc.. What happened was that when I picked the phone up, I had a nasty weird sound or some went like "tick, tick, tick". Opened the phone up and changed a couple of caps that went dry. The phones were working fine as kind after the repair.

[goontron]

Re: Telefonica Amper Teide (D) classic corded phone repair (solved)

Blown bridge..... Probably got hit by lightning.

[Chungalin]

Re: Telefonica Amper Teide (D) classic corded phone repair (solved)

I thought that, but not so easy to prove! From my quick circuit analysis, the diode bridge only gets in circuit when you lift the receiver. When the phone is idle, the receiver switch (SPDT) switches to another part of the circuit. As I said before, the phone was able to ring.

And I mean that my mother (who is the only one that uses this phone) would never call during a electric storm.