Here's a quick fix that somehow escaped getting posted over the years. The symptom is simple. Your built-in LED frequency display goes dark. RCI-made radios have all manner of brand-name badges on them, but what really matters is the production year.
This failure will also be seen in the various external versions made by RCI with names like Galaxy and Texas Ranger on the outside.
The original "Galaxy" radios with the built-in 5-digit counter had a module that was two-thirds the width of a mobile radio. In 1995 RCI upgraded their display technology and shrunk the counter module down to an inch and a half by two and a half. It got revised more than once, but the example we have here to day has the circuit board number "EPT210014C". Got used from 1995 to around Y2K, more or less.
It will spontaneously go dark. As you'll see in this example, a tech's first impulse is to replace the three-terminal 5-Volt regulator chip. Would normally have the type "7805T", or maybe "340T-5". Korean and chinese suppliers have their own number schemes. This tech had some really old stock. The "SK" series of replacement semiconductors went dark a long time ago. It was a product of RCA. You know how long ago they got dismembered and flushed. The date code on this regulator chip is 1994. Good thing they have a really good shelf life.
But changing the chip didn't make it light up, so I got the job. As it turns out all you need to fix this fault is a 47-ohm 1/4-Watt resistor and teflon sleeve to insulate the long leads.
Here's the fix on the top side.
All we're doing is jumping around a surface-mount resistor that serves to drop some of the 13.8-Volt power down to 8 or 9 Volts into that 5-Volt regulator chip. The resistor goes open and the counter goes dark. No need to molest the failed part. Simply completing the lost circuit this way does the job.
The power comes in from a 2-pin plug. This is the hot pin where the other end of the resistor connects.
If this doesn't fix the problem at least you didn't waste a lot to find out. Then again, that fat regulator is easy to check. If you have at least 9 Volts on the outboard-side pin and don't have 5 Volts on the inner-side pin, that chip may be at fault. At least its a cheap generic component.
73
This failure will also be seen in the various external versions made by RCI with names like Galaxy and Texas Ranger on the outside.
The original "Galaxy" radios with the built-in 5-digit counter had a module that was two-thirds the width of a mobile radio. In 1995 RCI upgraded their display technology and shrunk the counter module down to an inch and a half by two and a half. It got revised more than once, but the example we have here to day has the circuit board number "EPT210014C". Got used from 1995 to around Y2K, more or less.
It will spontaneously go dark. As you'll see in this example, a tech's first impulse is to replace the three-terminal 5-Volt regulator chip. Would normally have the type "7805T", or maybe "340T-5". Korean and chinese suppliers have their own number schemes. This tech had some really old stock. The "SK" series of replacement semiconductors went dark a long time ago. It was a product of RCA. You know how long ago they got dismembered and flushed. The date code on this regulator chip is 1994. Good thing they have a really good shelf life.
But changing the chip didn't make it light up, so I got the job. As it turns out all you need to fix this fault is a 47-ohm 1/4-Watt resistor and teflon sleeve to insulate the long leads.
Here's the fix on the top side.
All we're doing is jumping around a surface-mount resistor that serves to drop some of the 13.8-Volt power down to 8 or 9 Volts into that 5-Volt regulator chip. The resistor goes open and the counter goes dark. No need to molest the failed part. Simply completing the lost circuit this way does the job.
The power comes in from a 2-pin plug. This is the hot pin where the other end of the resistor connects.
If this doesn't fix the problem at least you didn't waste a lot to find out. Then again, that fat regulator is easy to check. If you have at least 9 Volts on the outboard-side pin and don't have 5 Volts on the inner-side pin, that chip may be at fault. At least its a cheap generic component.
73
