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Post by Night Ranger on Nov 16, 2012 20:51:53 GMT -5
I have a Realistic TRC-451 I am attempting to restore. The channel LED display has a segment burned out in it. The part number on the LED that came with the radio is UR-202D-46-DL. After searching around on the Internet I found a website claiming the Workman 4233RA replacement LED display would work, so I ordered the part. See... www.kenselectronics.com/lists/leds.htmThe new parts has the same number of pins in the same same shape, but when I soldered in the new LED display nothing happens. I looked over all my connections with a magnifying glass and it all looks good with no stray solder. I have the little notch on the bottom lined up with the notch on the printed circuit board and the printed side is facing up. Has anyone else successfully replaced the LED channel display on a Realistic TRC-451? Night Ranger |
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Sandbagger
Administrator/The Boss 
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Post by Sandbagger on Nov 16, 2012 22:57:07 GMT -5
I have a Realistic TRC-451 I am attempting to restore. The channel LED display has a segment burned out in it. The part number on the LED that came with the radio is UR-202D-46-DL. After searching around on the Internet I found a website claiming the Workman 4233RA replacement LED display would work, so I ordered the part. See... www.kenselectronics.com/lists/leds.htmThe new parts has the same number of pins in the same same shape, but when I soldered in the new LED display nothing happens. I looked over all my connections with a magnifying glass and it all looks good with no stray solder. I have the little notch on the bottom lined up with the notch on the printed circuit board and the printed side is facing up. Has anyone else successfully replaced the LED channel display on a Realistic TRC-451? Night Ranger My 451 has intermittent segments. Jiggling the swtich (dirty contacts) or sometimes pressing on the display will temporarily correct the problem. The reason your replacement display is not working may have something to do with the configuration of the LED's. There are two types of 7 segment displays, common cathode, and common anode. If you get the wrong type, the polarity will be reversed and it wont work. |
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Post by Night Ranger on Nov 17, 2012 3:44:41 GMT -5
I have a Realistic TRC-451 I am attempting to restore. The channel LED display has a segment burned out in it. The part number on the LED that came with the radio is UR-202D-46-DL. After searching around on the Internet I found a website claiming the Workman 4233RA replacement LED display would work, so I ordered the part. See... www.kenselectronics.com/lists/leds.htmThe new parts has the same number of pins in the same same shape, but when I soldered in the new LED display nothing happens. I looked over all my connections with a magnifying glass and it all looks good with no stray solder. I have the little notch on the bottom lined up with the notch on the printed circuit board and the printed side is facing up. Has anyone else successfully replaced the LED channel display on a Realistic TRC-451? Night Ranger My 451 has intermittent segments. Jiggling the swtich (dirty contacts) or sometimes pressing on the display will temporarily correct the problem. The reason your replacement display is not working may have something to do with the configuration of the LED's. There are two types of 7 segment displays, common cathode, and common anode. If you get the wrong type, the polarity will be reversed and it wont work. I've sprayed the channel selector with contact cleaner, and it does not seem to make any difference on this TRC-451. The actual segment appears to be burned out. I've searched the Internet trying to find a datasheet for both LED's, but so far I have not found anything. There are a few websites selling the Workman 4233RA part, but the most information about it they show is a picture of it. I did find this helpful pdf on LED displays; hibp.ecse.rpi.edu/~connor/education/IEE/lectures/Lecture_7_digital_display.pdfNight Ranger |
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Sandbagger
Administrator/The Boss
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Post by Sandbagger on Nov 17, 2012 10:06:15 GMT -5
My 451 has intermittent segments. Jiggling the swtich (dirty contacts) or sometimes pressing on the display will temporarily correct the problem. The reason your replacement display is not working may have something to do with the configuration of the LED's. There are two types of 7 segment displays, common cathode, and common anode. If you get the wrong type, the polarity will be reversed and it wont work. I've sprayed the channel selector with contact cleaner, and it does not seem to make any difference on this TRC-451. The actual segment appears to be burned out. I've searched the Internet trying to find a datasheet for both LED's, but so far I have not found anything. There are a few websites selling the Workman 4233RA part, but the most information about it they show is a picture of it. I did find this helpful pdf on LED displays; hibp.ecse.rpi.edu/~connor/education/IEE/lectures/Lecture_7_digital_display.pdfNight Ranger Assuming the pinouts for displays are the same, I'd be willing to bet you have the wrong configuration display. The TRC-451 uses a common anode display. |
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Post by Night Ranger on Nov 17, 2012 10:17:48 GMT -5
I've sprayed the channel selector with contact cleaner, and it does not seem to make any difference on this TRC-451. The actual segment appears to be burned out. I've searched the Internet trying to find a datasheet for both LED's, but so far I have not found anything. There are a few websites selling the Workman 4233RA part, but the most information about it they show is a picture of it. I did find this helpful pdf on LED displays; hibp.ecse.rpi.edu/~connor/education/IEE/lectures/Lecture_7_digital_display.pdfNight Ranger Assuming the pinouts for displays are the same, I'd be willing to bet you have the wrong configuration display. The TRC-451 uses a common anode display. I have Krazy Ken's old TRC-451. It works sort of. It has reduced output, but I'm not sure why yet. It is the same TRC-451 he threw out his bedroom window when the window was still closed after I aggravated him to a moment of temporary insanity. I suppose I could rob the display out of that one if I had too, but I'd rather just find a new replacement for it if possible. Night Ranger |
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Post by Night Ranger on Nov 17, 2012 10:20:54 GMT -5
I've sprayed the channel selector with contact cleaner, and it does not seem to make any difference on this TRC-451. The actual segment appears to be burned out. I've searched the Internet trying to find a datasheet for both LED's, but so far I have not found anything. There are a few websites selling the Workman 4233RA part, but the most information about it they show is a picture of it. I did find this helpful pdf on LED displays; hibp.ecse.rpi.edu/~connor/education/IEE/lectures/Lecture_7_digital_display.pdfNight Ranger Assuming the pinouts for displays are the same, I'd be willing to bet you have the wrong configuration display. The TRC-451 uses a common anode display. I just had a thought. I should be able to use the diode checker function on my multi-meter to determine the direction of current flow on the new digital display. Then I could compare that to the direction of current flow on the radio. If they don't match I could surmise that I have the wrong part. Night Ranger |
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Sandbagger
Administrator/The Boss
Posts: 6,247
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Post by Sandbagger on Nov 17, 2012 10:21:56 GMT -5
Assuming the pinouts for displays are the same, I'd be willing to bet you have the wrong configuration display. The TRC-451 uses a common anode display. I just had a thought. I should be able to use the diode checker function on my multi-meter to determine the direction of current flow on the new digital display. Then I could compare that to the direction of current flow on the radio. If they don't match I could surmise that I have the wrong part. Night Ranger Great idea! That'll do it. |
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Post by Night Ranger on Nov 17, 2012 17:57:36 GMT -5
I just had a thought. I should be able to use the diode checker function on my multi-meter to determine the direction of current flow on the new digital display. Then I could compare that to the direction of current flow on the radio. If they don't match I could surmise that I have the wrong part. Night Ranger Great idea! That'll do it. Well the diode test on the replacement part is backwards from the stock part, so it does not appear it is going to work. Night Ranger |
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Sandbagger
Administrator/The Boss
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Post by Sandbagger on Nov 17, 2012 21:13:43 GMT -5
Great idea! That'll do it. Well the diode test on the replacement part is backwards from the stock part, so it does not appear it is going to work. Night Ranger Not surprised at what you found, but I'm puzzled since the part you cross referenced states that it's common anode, which is the correct configuration. Maybe they sent you the wrong part. |
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Post by Night Ranger on Nov 18, 2012 5:12:19 GMT -5
Well the diode test on the replacement part is backwards from the stock part, so it does not appear it is going to work. Night Ranger Not surprised at what you found, but I'm puzzled since the part you cross referenced states that it's common anode, which is the correct configuration. Maybe they sent you the wrong part. The part they sent me has "4233RA" printed on the side of it which is what is printed on the web page. "UR-202D-46-DL" is what is printed on the original part. Night Ranger |
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Sandbagger
Administrator/The Boss
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Post by Sandbagger on Nov 18, 2012 10:13:13 GMT -5
Not surprised at what you found, but I'm puzzled since the part you cross referenced states that it's common anode, which is the correct configuration. Maybe they sent you the wrong part. The part they sent me has "4233RA" printed on the side of it which is what is printed on the web page. "UR-202D-46-DL" is what is printed on the original part. Night Ranger So I guess we blame the factory for stamping the wrong part?  |
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Post by 2600 on Nov 18, 2012 23:55:34 GMT -5
Here's the data I have on that part, from my bench notes. The first Uniden 40-channel SSB CB radios used a display made by Toshiba, called the "TLR-321". They sold the rights for it when the market was no longer new and growing. Dozens of vendors have sold them to Uniden in the years since, each one using their own particular part number.
The file below did not preserve column positions, so the pinout diagram looks all wrong. The two center pins on the bottom row are the common-anode pins, one for each digit. Maybe I'll try to tweak this later. The file looks fine in Wordpad...
73
Filename: TLR-321.DAT LAST UPDATED 1/8/99 C.R.
----->> NOTICE !! NO DECIMAL POINT ON THESE DISPLAYS <<----
--PINOUT FOR TLR-321 (KLR-321) 2-DIGIT RED LED DISPLAY, 2-DIGIT
DIRECT-DRIVE USED IN EARLY 40-CHANNEL CB RADIOS.
--UR202-2Y RED
--LDG-202ALD (MFR UNK) GREEN DISPLAY, USED IN PRO538W IS SAME
W/LONG LEGS. UNIDEN PART# BDAY0187001
--LTD482GC IS GREEN EQUIVALENT USED IN PC76XL. UNIDEN PART # IS
BDAY0755001 -> HAS SHORT (3/16" L.) LEGS. TYPE LETTERING IS ON
* TOP * OF THIS SERIES OF PARTS (DECIMAL POINTS VISIBLE IN THE
MASK IN FRONT WILL BE ON THE BOTTOM EDGE).
--LTD482RC IS RED, LTD482EC IS RED/ORANGE. LITON ORIGINAL
NUMBERED PARTS FROM DIGI-KEY ARE CHEAPER THAN GETING THEM FROM
UNIDEN AS OF 1/99 C.R.
R E A R V I E W
(type number on top surface)
-----------------------------------
| o o o o o o o o |
| g a f b b f a g |
| |
| -units- -tens- |
| |
| c e d d e c |
| o o o o o o o o |
|----------------------------------
^ ^
| |
common anode units-- ---common anode tens digit
!!! NOTE !!!
LTD432DP IS * COMMON CATHODE * VERSION OF ABOVE RED DISPLAY, SAME
PINOUT.
UL1421 IS GREEN EQUIVALENT MADE BY U-JIN OF KOREA, BOUGHT FROM
DNA DISTRIBUTING LATE 1997.
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Post by BBB on Nov 22, 2012 8:43:40 GMT -5
I'm reading that these TRC-451 radios have good audio due to a built in speech processor?
Is this the same as a Cobra 146GTL or a Sears RoadTalker 663.38100050? If so I'd like to see what the Sears equivalent looks like.
I'll have to keep my eye to the curb for one of these TRC-451 rigs or maybe better yet a TRC-450 with a more modifiable PLL.
Maybe there's a cheaper AM only version that you could find and snatch the LED's out of also.
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Post by Night Ranger on Dec 3, 2012 14:40:17 GMT -5
Well it appears the part I have is just plain the wrong part. Oh well.
Thanks for the help though.
Night Ranger
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Post by rob2063 on May 24, 2022 18:32:44 GMT -5
The TRC-451 uses the 4233RA display, it should work. Check to see if there is voltage (8V) at pins 3 or 4 of the display
if no voltage is present, check TR401 and D402 of the dimmer circuit for voltages.
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