a real challange?

[Kevin Kuehn]

Heck if you're actually using Sams 74-3, that schematic shows the complete audio output stage. Look at the chassis layout, it shows the locations for the 6At6 audio amp and 6K6 audio output.

[Yamamaya42]

Originally Posted by Kevin Kuehn

Can you see the octal tube socket hole right next to the tuner? That was punched for an optional 6K6 audio output amp. You'd need to add an audio output transformer and volume pot, but man this would be so simple to add the amp stage right on your TV chassis. There may even be an extra control mounting hole on the front of your chassis? Fada made a model 925 TV only chassis that I'm pretty sure used the same basic chassis layout as your 895, which is why the hole for the optional audio output is there next to the tuner. I can post the schematic section from the 925 and you can wire it accordingly, that is if you're up for the challenge?

https://i.imgur.com/oFR1Zab.jpg

It's actually on the other side hidden under a metal plate.
This COULD be done, but I would have to get a 6k6 (I doubt a 6v6 would be happy in there), I have the output x-former I was going to use in this project, I'd also have to work out what they changed for the 895 version and un-do it, and find SOMEPLACE to put the volume cont, as there is no place to put it since they moved everything around to make room for the 12 inch crt.

[Kevin Kuehn]

Originally Posted by Yamamaya42

It's actually on the other side hidden under a metal plate.
This COULD be done, but I would have to get a 6k6 (I doubt a 6v6 would be happy in there), I have the output x-former I was going to use in this project, I'd also have to work out what they changed for the 895 version and un-do it, and find SOMEPLACE to put the volume cont, as there is no place to put it since they moved everything around to make room for the 12 inch crt.

I beg to differ. I can clearly see daylight showing through the mounting hole for the 6K6 as shown in your picture. Possibly the plate you refer of is the bottom shield for the tuner? Also the earth is still littered with good used and NOS 6K6's. But if you don't want to mess with this I fully understand.

[Kevin Kuehn]

I made a red arrow pointing to the hole for the 6K6(V16 on your sams). V14 and V15 are also right there along that inside angled edge of the chassis. Sams pictorials even shows where output transformer and all the missing components will go. You will not be undoing hardly anything. You'll simply be taking the existing audio output wire and connecting it to some added circuitry. It could not be any easier if it were a Heathkit. If you can recap an entire TV, surely adding a few components to a pre-punched chassis will be a piece of cake?

[Electronic M]

The 6K6, 6V6, and 6L6 were listed as replacements for each other in some tube substitution books. You could probably build it with a 6V6 and swap to a K later on...

[Yamamaya42]

Originally Posted by Kevin Kuehn

I beg to differ. I can clearly see daylight showing through the mounting hole for the 6K6 as shown in your picture. Possibly the plate you refer of is the bottom shield for the tuner? Also the earth is still littered with good used and NOS 6K6's. But if you don't want to mess with this I fully understand.

you are right about the hole for the 6K6, i got turned around ( :/) but there is a plate in the way, you just cant see it , i must get better pics.

you can see a screw for it in this top view in one of the holes for the 6K6 socket.
https://imgur.com/adDUoEM
its covering the area for v14/v15
not sure what it is there for.
i will try to remove it a look :/
I wish there was a SAMS for this, it is just different enough.

also, finding a 1m center-tapped pot may be tricky...

[Kevin Kuehn]

Originally Posted by Electronic M

The 6K6, 6V6, and 6L6 were listed as replacements for each other in some tube substitution books. You could probably build it with a 6V6 and swap to a K later on...

Absolutely!

Maybe I'm imagining things, but is this a hole where a volume control/power switch could be missing from, or is something else(the moved focus) suppose to go there? It's very near where Sams shows the volume/on/off control.

[Kevin Kuehn]

Originally Posted by Yamamaya42

also, finding a 1m center-tapped pot may be tricky...

Not. You really wouldn't need the loudness tap on a TV. Although used ones of those are not exactly scarce.

[Electronic M]

I might have such a pot in my stash...

[Yamamaya42]

Originally Posted by Kevin Kuehn

Absolutely!

Maybe I'm imagining things, but is this a hole where a volume control/power switch could be missing from, or is something else(the moved focus) suppose to go there? It's very near where Sams shows the volume/on/off control.

it was removed, to make room for the larger CRT, the bezel covers that up

if you look at this low-rez pic here, you can see where the hole would have been for it,,
https://imgur.com/LO6LqLa

so I can leave the 1 m resistor and .01 cap off of that vol cont ( center tap) and it wont matter? :O

[Electronic M]

Originally Posted by Yamamaya42

it was removed, to make room for the larger CRT, the bezel covers that up

if you look at this low-rez pic here, you can see where the hole would have been for it,,
https://imgur.com/LO6LqLa

so I can leave the 1 m resistor and .01 cap off of that vol cont ( center tap) and it wont matter? :O

Basically what that tap and the parts on it did was adjust the tone in step with the volume to make the tone consistent across the volume range...it's been a decade since I read that in an amp building article in a 50's electronic magazine so I could be mis- remembering...try googling volume control VS loudness control. The tap and it's tonal compensation are the difference between the two IIRC.

[Kevin Kuehn]

Originally Posted by Yamamaya42

it was removed, to make room for the larger CRT, the bezel covers that up


if you look at this low-rez pic here, you can see where the hole would have been for it,,
https://imgur.com/LO6LqLa

so I can leave the 1 m resistor and .01 cap off of that vol cont ( center tap) and it wont matter? :O

It will have a tonal effect at lower volumes.
IMO not a deal breaker, at least not when you can replace it with a taped control at any point down the road. If anything it will be very brilliant sounding in the mid range, compared to loudness compensated. If this were my set I'd be focusing on getting it minimally effort operational and tweak the little things after you come up with a completion game plan. Also there's a good reason why the manufacture kept all the audio tubes and volume control in that very confined area.

[Kevin Kuehn]

By the way, I can make you copies of the Riders pages specific to your model 895, but they are 11"x17" format, so I need to go to a print shop to do it. I have no way to scan those large pages. I have no idea what it will cost to mail those pages, but probably not too much if you don't mind them being folded in half. But honestly I think many folks find Riders schematics more difficult to follow, and when you try using them combined with Sams, it will get even more confusing.

[Yamamaya42]

here is the bottom view with the plate ( not seen on other versions )
https://imgur.com/EilsJ38
you can see the audio wire coming out

will have to remove it to see how all is wired.

https://imgur.com/ILIgrW8

top view
wire soldered to edge of tube socket hole, and wires coming out where audio x-former would go.

[Kevin Kuehn]

Originally Posted by Yamamaya42

here is the bottom view with the plate ( not seen on other versions )
https://imgur.com/EilsJ38
you can see the audio wire coming out

will have to remove it to see how all is wired.

https://imgur.com/ILIgrW8

top view
wire soldered to edge of tube socket hole, and wires coming out where audio x-former would go.

That is a shield because the signal level is so low at the detection point. You really should not need to disturb much under there.

I took these hand held photos of what Riders has on the model 895. You can compare the audio section to your Sams. I did not study it in depth, but it appears basically the same minus your set is not using the 1st audio or output tubes. It's curious that your chassis actually has the 6AT6 1st audio tube installed, but it's not being used.

If you want to keep these Riders pages you'd better save them because I can't promise how long they will be posted on my Flickr page.

https://www.flickr.com/photos/152661...57713086856613