I worked in the paging industry back in the 80’-90’s and the BRAVO pager from the big M was the pager of choice. The biggest problem was with the display. We had purchased hundreds of expensive control boards to replace broken displays. We finally were able to obtain a heat bonding station from the big M parts depot as well as a case of displays, pad cleaning pens, flux, etc. during the quiet times we would clean off ten at a time the control boards and then proceed to lightly flux the pads on the boards. One then places the board in the alignment jig and adds the display. At this point the heater has been preheating for at least ten minutes. You could then lower the heater head onto the joint and time it for X number of seconds as prescribed by M. Bingo a new display and another control board saved. Basically the flex circuits have been designed to use a heat bonding machine with a specific temperature for the solder used on the pre tinned display. A silicone strip in front of the heating element protects the flex board while providing the proper amount of heat and pressure to complete the soldering process. Now if I only had that press, perhaps I could have designed or modified it for the longer heat strip needed for the 857 displays. There is an adhesive strip just above the strip contacts, any idea what might be used in place of the original? It’s double sided and is used as "insurance policy" against accidentally ripping off the display from the control board if some novice takes their unit apart as well as for holding the flex in place for soldering.
I dont mind the missing one line on my display. After you changed my ceramics. Its like a new radio again. Andy we hope youre training and passing along this info. None of us are getting younger and most young ppl cant fix a gd thing. 🙏✌️🇺🇸
I worked in the paging industry back in the 80’-90’s and the BRAVO pager from the big M was the pager of choice. The biggest problem was with the display. We had purchased hundreds of expensive control boards to replace broken displays. We finally were able to obtain a heat bonding station from the big M parts depot as well as a case of displays, pad cleaning pens, flux, etc. during the quiet times we would clean off ten at a time the control boards and then proceed to lightly flux the pads on the boards. One then places the board in the alignment jig and adds the display. At this point the heater has been preheating for at least ten minutes. You could then lower the heater head onto the joint and time it for X number of seconds as prescribed by M. Bingo a new display and another control board saved. Basically the flex circuits have been designed to use a heat bonding machine with a specific temperature for the solder used on the pre tinned display. A silicone strip in front of the heating element protects the flex board while providing the proper amount of heat and pressure to complete the soldering process. Now if I only had that press, perhaps I could have designed or modified it for the longer heat strip needed for the 857 displays.
There is an adhesive strip just above the strip contacts, any idea what might be used in place of the original? It’s double sided and is used as "insurance policy" against accidentally ripping off the display from the control board if some novice takes their unit apart as well as for holding the flex in place for soldering.
I dont mind the missing one line on my display. After you changed my ceramics. Its like a new radio again. Andy we hope youre training and passing along this info. None of us are getting younger and most young ppl cant fix a gd thing. 🙏✌️🇺🇸
Very nice sir. I'm super happy with the repair you did on mine
Truly impressed, but what a Pain in the back side to do all that soldering. Now I know who to call if I ever have this issue.
Andy does amazing work 👍🙏
Andy, any idea where I can find a good narrow CW filter for the 857 ?
I think I have a 300hz filter I need to check. Can you email me andyit28@gmail.com