Algo Duet-Plus 1825(p) not warbling repair

[CapLeaker]

Got one of these Algo Duet-Plus 1825(p) in for repair. Complaint: Not making any noise anymore.

Yeah... and nope it wasn't the LM384N audio amp. The warbler IC is the MC34017A-1P. In short, if you press that test button a warble sound comes out that speaker. In my case I injected a tone with my tone generator on pins 2 and 3 on MC34017A and sure enough... sound was getting to pin 6 of the LM384N and amplified out to the speaker.
Hmm... o.k. is the IC getting turned on pin 4 when I press the button? Yep. Is really that warbler IC bad? Sure enough... dead like a door nail.

It's an interesting device. Weird enough for this section.

[stj]

Re: Algo Duet-Plus 1825(p) not warbling repair

interesting chip,
too bad most of the western world is going to switch to voip soon to save money (at their end, not ours)

[CapLeaker]

Re: Algo Duet-Plus 1825(p) not warbling repair

Talking about VOIP. My work place just switched over to VOIP. For my line of work, it's for the better, since I can take the phone where I need it. I just need an internet connection and that's it. Matter effect I tried it today using Starlink on a remote site and I had phone and internet, where previously only satellite phone worked. It really depends on the line of work.
Other than that, price wise, the landlines were actually cheaper as work had a contract with the phone company. BUT: Now we need only 25% of all the phone lines we had before.

[stj]

Re: Algo Duet-Plus 1825(p) not warbling repair

i remember when you could use the fone if the power failed.
even if you have a ups type of setup, how long will voip run? not days i'm sure

with copper pair dialup all you need is a handset or linemans fone and access to the wires
no extra power required.

[CapLeaker]

Re: Algo Duet-Plus 1825(p) not warbling repair

I remember those rotary phone days… I also remember making a little charger that plugs into the phone line and charges the batteries. I also remember other things that worked back in the 90’s. Kinda was fun. Or how about repairing modems and fax machines! Oh boy… I am getting old!

[redwire]

Re: Algo Duet-Plus 1825(p) not warbling repair

I once made a telephone ringer using I think AMI Gould S2561A.
It was fun until the fancy IC croaked, something to do with the piezo capacitance holding too much charge and the IC output stage blew. After all that work it lasted maybe 10 rings
https://datasheetspdf.com/pdf-file/5...uctor/S2561A/1

[CapLeaker]

Re: Algo Duet-Plus 1825(p) not warbling repair

Hmm... interesting, that the S2561 failed the same way that this MC34017, just with an extra short life span. lol. Apparently this MC34017 sounded different (probably like a cat dying) before it died. When I got it, it was absolutely dead, no audio at all. I found some of these MC34017's at futurelec.

[CapLeaker]

Re: Algo Duet-Plus 1825(p) not warbling repair

To round it all up, I never got the order from futurelec. Reordered at Ali, put the new MC34017 and the unit is working once more. A fourty cent part… lol.