Efforts to fix my three Radio Shack (Archer/Optimus) TV/FM line amps...

orange

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#1
Model 15-1113 should be for all, this model was made for several years under three brands for Tandy/Radio Shack Corporation. There is only one real variation other than chrome or black/grey case color when you look at the outside and that is a recessed switches (gain especially)...the FM trap switch does come out a little but the gain is either a shaft or recessed rotary pot.

I have had problems with the the gain control all messed up and the signals breaking/noise. I finally noticed that the case has four screws that hold the bottom on (D'oh) and so I removed the nuts on the coaxial connectors to free the board and sprayed the CDC QC. I only have my own toothbrush as my friend suggested but I found my Blow Off cans...the gain wheel is pretty fragile looking and sits on it's legs like a transistor. carefully spinning it would be a better idea and using the air again. I sprayed the QD 3X first. I have enough canned air to handle all three amps.

This one is the test subject.

Now, to continue...

Good/bad?

It was a trick to get the male coaxials back in right but then I found that ubiquitous large washer on the floor that I didn't recognize so I took it apart again and thought maybe it goes over the top of the gain wheel.

Not sure how that works or stays. Had to open it again and shake it out.

Now the part I worry about.

At least one part of the opposite side (not the coax side) is point soldered to the case with a single strand of bare wire (I assume for GROUNDING). There are TWO blobs of solder, one on each end. Only one has a wire attached.

Now they may also serve to anchor the board at a fixed level. IF one is a broken ground it should show as a signal problem, or ???

I'll try and draw a simple diagram or two as I don't want to take it apart again unless I have to and I'll be testing it out in before dinnertime.

Hang on this is a thread currently in editing progress.
 
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orange

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#2
It's tricky to get the male coax connectors in and out.

Of course you have to remove the flat nuts at the bottom that hold them steady, but then you need to CAREFULLY nudge one down a little then the other (they sorta of only go down a couple turns at a time until the top of the PCB is freed).

But there you must be very careful AGAIN, as at least one side of that edge is point soldered to the case with a short length of bare wire...I assume for grounding. There are two solder blobs and I saw only one wire. I don't believe I broke or lost any other so maybe they double as anchors for that side of the PCB.

Once you get done with cleaning (CRC QD 3X sprays then canned air along with gentle rotation of the gain wheel) you have to fit the coaxials back in the case holes with the aid of a tool (screwdriver tip works well with light pressure against the PCB inside) so that they slip back in together (not easy)! Then you replace the flat nuts and case screws to close the unit.

AND HOPE.
 

orange

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#3
It's a good thing that I bought a tub of Rocky Road ice cream when I was at the pharmacy to get my Rx...had a double cheeseburger after I cleaned up as well.
 

orange

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Pretty much great news! I have most of the channels back in the bedroom now!

The two main exceptions were not my making. The station with Oregon Public Broadcasting (OPBT30) that moved from RF15 30 after a limited repack a few months ago had been using the PSIP virtual channel number of 3.1 and whern they changed that to 13.1 (which is that of the LaGrande affiliate KTVR) all of a sudden you would see a signal supposedly there but with nothing on it. Once I went to the website and caught on to do a complete rescan I got OPB back as OPBT30 13.1 but and I got some signals that were hard to register and one I've never seen before on 27.1 yet I was missing the station with 12 TV and audio/radio channels...

Once I visited their website I learned that they were temporarily OFF THE AIR from a transmitter issue so they could 'avoid a critical failure' (overheating).

So I fixed the amp! :cool:
 
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orange

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NOW the problem is that I actually have to leave the amp in the bedroom UNPLUGGED or that's a noisy overloaded mess. Problem is that I get 5 stations.

OTOH They have been showing classic NCAA Basketball Tournament highlights on CBS, Golf Channel reruns on NBC and boxing on FOX.

Please God, make them show more F1 and NASCAR repeats.
'
 

orange

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More progress!

First, I think I finally isolated most of the problem with the bedroom drop.

I have been using an AV switcher with a coax out for the old non-RCA equipped Trinitron.

I removed the amp from the line and all else and ran straight to the DTV box.

Bingo! Most of the channels returned but three are still weak.

I have a video preamp with six outputs, two for long drops and four short.

I made sure that the Two TV lines are on the long drops and I have nearly every signal available to me at this location.

I'm tweaking the bedroom drop up front to get as much as I can.

I have this switcher because I don't have RCAs on my 70s/80s Trinitrons, not a one of the three. I was using the switcher for the coaxial outputs of the DTV converter and LD/DVD player.

IF I can replace the tire for my Mitsubishi HS-U70 Twin Digital VHS Hi-Fi deck as Nakdoc instructed me then I can use the two lines on it for the DTV and LD/DVD and hopefully not suffer too much of a signal loss there. Or I can use it as a switch while waiting for my Sony to return from him (and it's DONE).

But it's almost 4 in the morning and I don't care if Margie's at the Lincoln Park Inn, I'm trying to finish my laundry including the bed linen and SLEEP.
 
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J!m

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#7
BAck in the 80's when we were dubbing VHS tapes that might have Macrovision "copy protection" on them, it was often necessary to run a signal amp/booster to keep the signal "hot". We could get around this (sometimes- depended on who made the original tape) by running a very short patch cord from machine to machine (no monitor) as that kept the signal strong enough to get a decent dub.
 

orange

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#8
I've got the channel with 12 signals up strong enough to watch without breaking up but oddly enough it the unplugged third amp's gain control works better than plugging it in, even without being part of anything else, just the wall to the amp to the DTV box. Take it out and that channel goes but 1-2 others return.

Sheesh. One more PBS station and digital 39 and I could watch Match Game and other old gems plus reruns again.

Buzz'r
Antenna
Cozi
Telemundo

OPB
OPB+
Kids
OPB-FM (OPB News, OPBMUSIC, KMHD Jazz Radio)

That 12 signal station has

NewsmaxTV
ThisTV
H&I
Decades
Movies!
Start
LightTV
RetroTV
KTSY (Christian Radio)
Project 88.7 KOAY (Christian hiphop)
ShopLC
NOAA Weather Radio

That's a lot of good TV!

I have 65 digital channels available in total and about 5 stations are dark at the moment. Even with duplications it's better than cable (and FREE).
 
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