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Post by husker on Jul 17, 2008 21:28:13 GMT -5
Ok, so I have finally decided that I can't fix the entire world today  So maybe I will start with one thing at a time. So with that in mind I decided that I have a wonderful, but well used D201 that would be a great place to start. It has a awesome receiver but puts out 9+ watts dead key so I know I have work to do. I have attached a pic of my BA brd from this radio, if you look in the top left corner you can see the green brd has turned black from heat, so i figured I would see what I should look at to replace here. Also when I touch the cover to anything metal I get static(grounding??) and I did find what looks to be a cut foil on the bottom side. Please review these pics and I would love any advise I can get! thanks in advance     |
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Post by Tombstone (R.I.P.) on Jul 18, 2008 7:06:23 GMT -5
Yeah, ground the radio if you can. I can't really get a good look at your pics but I think I can see the cut trace, does it have the two yellow wires soldered to each side? If so I'm not sure those wires should be there, is there a switch on the yellow wires? If this is the case that might be some kind of power modification so do away with that, strap across the cut trace and look for lower than factory value power resistors and replace them with the correct value and use a higher wattage rating. 9+ watts out will cause problems. This is just a guess from what you say and what I can see in the pics. Also check the resistors on the BA board and make sure that the connector pins all fit snugly. If someone jacked up the power that's probably why the board has a burnt area on it.
Tombstone
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Post by husker on Jul 18, 2008 11:47:08 GMT -5
Ok, as far as the BA brd, would it just be a better/easier idea to just buy a new one from Greg???
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Post by Tombstone (R.I.P.) on Jul 18, 2008 18:31:29 GMT -5
Now that's a good thought!
Tombstone
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Post by husker on Jul 18, 2008 18:56:38 GMT -5
I know, but I want to learn...everyone's gotta start somewhere!
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Post by Tombstone (R.I.P.) on Jul 19, 2008 6:00:27 GMT -5
I understand. Then you'll have to try and repair the BA board. You'll need a schematic of the radio to see if those yellow wires are supposed to be there and especially if there are resistors on the board that are cooked to the point that you can't read the color bands. You'll have to find out if the power resistor(s) to the final driver and the final are correct and you'll need to check for proper voltages from the power supply and check for smooth DC coming out of it in case of a bad rectifier or filter caps. You'll need an ocilloscope for that. be VERY careful when testing high voltages, that can kill. I'm not tying to downgrade you but I'm not responsible for any damage or electrocution if you try my suggestions. I couldn't live with myself if you get killed by doing something that I told you about. I assume that you can read schematics? Also, with most tube type equipment you'll need to measure negative voltage and you'll need a VTVM for that, a VOM isn't enough. Good luck!
Tombstone
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Post by husker on Jul 19, 2008 12:54:04 GMT -5
Actually there is a jumper that was put in place after the trace was cut. So I intend to cut that jumper and redo the trace. What is the best way to fix that cut with a circuit brd that is this old. Should I just put a jumper in over the cut??
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Post by Tombstone (R.I.P.) on Jul 19, 2008 13:12:11 GMT -5
Yes, just solder a jumper across the cut trace. What is the jumper that you're going to remove connected too? That might be part of your problem.
Tombstone
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Post by husker on Jul 19, 2008 21:16:24 GMT -5
I am using an other D201 I have as a reference point....it doesn't have the traces cut...
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Post by 2600 on Jul 23, 2008 23:39:59 GMT -5
The one with the cut traces is probably a 40-channel D201A.
The 23-channel radio used a half-dozen round beige-colored ceramic filters for the AM (only) side of the receiver. Around the time the 40-channel radio went into production, this part was discontinued. At first, they would use a small, black square-shaped filter along with two of the older round beige parts.
Later on, they used two of the small, square black ceramic filters. If your radio has two of these, there would be cuts and jumpers in the foils of the main receiver board. This was part of the modification to use the later-type AM ceramic filters.
And if this is a 23-channel D201, maybe I'm wrong and someone simply butchered it?
73
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Post by husker on Jul 23, 2008 23:44:21 GMT -5
It is a 201 and you are correct saying someone butchered it...it's a shame, but it is now a challenge to get it back to where it belongs
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Sandbagger
Administrator/The Boss 
Posts: 6,247 
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Post by Sandbagger on Jul 24, 2008 7:03:59 GMT -5
The one with the cut traces is probably a 40-channel D201A. The 23-channel radio used a half-dozen round beige-colored ceramic filters for the AM (only) side of the receiver. Around the time the 40-channel radio went into production, this part was discontinued. At first, they would use a small, black square-shaped filter along with two of the older round beige parts. Later on, they used two of the small, square black ceramic filters. If your radio has two of these, there would be cuts and jumpers in the foils of the main receiver board. This was part of the modification to use the later-type AM ceramic filters. And if this is a 23-channel D201, maybe I'm wrong and someone simply butchered it? 73 One of my 23 channel D-201's has the AM ceramic filter mod. It's evidently one of the last production D201's before the D201A came out. It also had the 3 pin A.C. plug. So there were some number of 23 channel radios made with that filter mod. |
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