On 2024/07/01 7:14 p.m., Jukebox Repairman wrote:

Does this have a mute relay in the amp like a Wurlitzer?

You need to get a proper manual for your beastie!

No, there is no mute relay in the factory amplifier for the 1428. The relay found inside the amp is the heater boost for a quick warmup. The relay should energize once the 5U4 kicks the HV into gear...

John :-#)#

On Mon, Jul 1, 2024 at 8:50 PM John Robertson via Jukebox-list jukebox-list@lists.netlojix.com wrote:

On 2024/07/01 12:02 p.m., ascott822 via Jukebox-list wrote:
> Sound went out suddenly on my 1428.  The amp has been re-capped
and tubes replaced 3 years ago. Wondering if there is a mute
switch I might could check and it’s location.
>
I don't think this machine had a mute, instead it warmed up really
fast
using a higher voltage for the tube filaments until the 5U4 got warm
enough that the HV would activate the heater voltage reduction relay.

Are all the tubes glowing? A bad 5U4 will cause a total lack of sound.

Do you hear any humming from the speaker? If the speaker has a field
coil is it warm after around 1/2 hour? That will indicate that the
5U4
and it's HV is working.

John :-#)#

I was about to write what you wrote. I'm working on a 1422 and found it sort of ingenious to use the same screw that holds the tone arm up from hitting the tray or record as it swings over, is also the mute. That's pretty cool in my book anyway. :)

But, I doubt that adjustment suddenly went off unless your needle fell out and the tone arm is going lower than normal.

A bad resistor at the speaker won't kill the sound. The model "O" amp I just worked on played fine with that resistor missing, the only problem is that the B+ voltages go a bit higher than they should. I don't know if any of the 1422's came with a PM speaker, but this one has one.

Although burned out filaments are rare, if you ever saw the way those suckers glow so bright when warming up, one could have burnt a filament. You should easily be able to see them glow on warm up, except the 6J5. For that one I'd just leave the amp on for 10 minutes on standby, or after playing a record, and see if the metal case gets warm or hot.

I am assuming that you checked the fuse?

And listen for the warm up relay inside the amp to click when the B+ gets high enough.

Does your amp have the tube type socket filter caps? If so, be sure they are not still in, or a pin or two are cut off so they aren't connected.

On 7/2/2024 6:46 AM, JIM & LAURIE DIRKSEN via Jukebox-list wrote:

This machine is muted by shorting the input. There is a little plate under the tonearm that shorts out when the tonearm is lowered at end of play. The speaker is usually a PM type with a 5K ohm resistor mounted to it. This resistor is undersized and frequently burns up. Check this and replace it with a 50 or 100 watt version. Good luck, Jim On Monday, July 1, 2024 at 03:03:09 PM EDT, ascott822 via Jukebox-list jukebox-list@lists.netlojix.com wrote:

Sound went out suddenly on my 1428.  The amp has been re-capped and tubes replaced 3 years ago. Wondering if there is a mute switch I might could check and it’s location.

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