Bought used Grant LT unknown add-on Board inside?

[443]

Bought this used Grant LT for $20. I see it's missing the AM Regulator, so I know that will have to be replaced. other than that I do not know what is up with the radio, have not tried to power it on yet.

Inside is this looks to be add-on circuit board, I don't think it's factory. I do not know what it is. I thought maybe echo but pots look stock, this is probably something else. The purple wire goes to R72 the Gray wire goes "maybe" to the Dynamic Squelch Control switch on front panel, Yellow wire goes to Banded end of D22. Can't tell where the red and black wires go to. Maybe this is part of the Dynamic Squelch Control junk? I don't know it's been a long time since I been inside a radio with that feature. Never messed with a Grant LT before, plenty of LX and 148/2000's in past.

There are some wires cut on some of the jumper plugs that go into the mainboard. Not sure why that is unless they just weren't needed from factory or it's been modded.

White and Black wires cut just behind (looking from front of radio) JV23/R94/C77

Yellow and Red Wires cut, White NOT cut, next to R44/JV48

Red wire cut next to L59

Two wire cut, Maybe dark green or brown and white next to C229, Black wire NOT cut.

So far that looks like all that is cut.

 

[red97k1500]

I have the same problem, but with a grant xl. Mine has wires coming off the main board that are clipped off and I can’t figure out where they should be terminating at.

Maybe some much more knowledgeable members than me will be able to chime in and help you.

 

[443]

I have the schematic and was pretty sure I could figure out where the wires were supposed to go, but it may be more trouble than I think. Haven't powered it up yet, need to replace that missing AM regulator transistor. Been messing around today, may not get to it till tomorrow. It was a "boneyard" radio, thought I'd save it from being hacked to death for parts. It's really clean for it's age, tag on back says Philippines, not sure what year it was made though, tag doesn't say.

It also has two little variable caps mounted on bottom of circuit board on the Crystal, I am assuming they did this to go outside of the regular 40 channels, there's another crystal behind the front panel all wired to the Hi/Low tone switch.

 

[443]

I have the same problem, but with a grant xl. Mine has wires coming off the main board that are clipped off and I can’t figure out where they should be terminating at.

Maybe some much more knowledgeable members than me will be able to chime in and help you.

BTW: I have a Grant XL and could probably help you with the wires. I have two of them, one is beat up parts radio, the other is the one I am using now and works fine, only mods it's had done is Clarifier Unlock that would have any wires moved around so I am sure I could help you figure out where your wires go. Post some pics of inside of yours.

 

[Low_Boy]

That is factory in the LT. The XL does not have that board.

 

[443]

That is factory in the LT. The XL does not have that board.

10-4 I guess it's for the DSC, the bracket looked factory, but with the wires added in the way they were, I wasn't sure. About to power this thing up and see what all is up with it.

 

[443]

SSB RX and TX work great. Talked to Jamaica on it for a few minutes. Clarifier is unlocked for RX and TX

AM RX works, no TX (light comes on, no output, guessing AM regulator missing might cause that LOL).

The Frequency Expansion is on the Hi/Low and BRT/DIM switches. Depending on the combination selected the radio covers just about everything from 26.515 to 28.045

The Factory AM Regulator is a 2SD1135? I probably have one, but I understand it needs upgrading anyway? It's a 100V/4A NPN BCE pinout TO-220 device. hfe is 60-200. What would be a good upgrade for it that I might have on hand? i.e. NOT a NTE part...

 

[443]

And can I just put it on the side of the PCB near the Audio Chip or should I wire/remote mount it on the back of the Chassis like the newer Grant XL's, and this LT are?

 

[443]

I have some TIP-41C 100V 6A BCE HFE min 30
or MJE3055T 70V 10A BCE HFE Min 20 Max 100
or 2N6488G 90V 15A BCE HFE Min 20 Max 150

Looks like any of them would work, the 2N6488G being the strongest current handling wise.

 

[443]

So... I decided to stay up a while and just fix the damn thing. I ended up using a TIP41C for the AM Regulator, seems to be fine. AM TX came to life. Then replaced the meter light with a green LED to kind of match the rest of the lights. Radio works great, definitely worth the $20 I paid for it.

 

[Low_Boy]

The one or two I have had are great SSB Radios.

 

[red97k1500]

Congratulations on getting yours up and running!

I just need to figure out where the black and white wires go

 

[443]

In my older grant (before the little connectors like in yours) those same wires go:

Black Wire to C75 R92 junction
White wire to Center leg of TR19

On your board there is probably an empty spot for a connector there. I'll take the cover off my newer Grant XL with those connectors and verify.

 

[443]

On the newer Grant XL like yours those wires go the Hi/Low Tone switch on front panel.

 

[443]

My newer Grant XL is PB-208AD main board, what is yours? Disregard on where they go on the older Grant XL, that's where they go for sure, but may have totally different circuit board traces than the Newer Grant XL