Frontier fr2007 resistor

[nixforshay]

Hello all, I recently acquired a Helbros led alarm watch in pretty good shape. However, upon cleaning battery acid leakage, I noticed that the resistor at the top of the module where fr2007 is printed, is missing. Would anyone know what the value of this resistor ? Thanks.

[Ole Joe]

The value of that resistor is 10 Meg Ohms. It is used as a bias resistor between the input/output of the oscillator amplifier to set the threshold of the amplifier to approximately 1/2 the total battery voltage. If you replace this resistor, make sure you DO NOT use a Lead bearing solder to remount it or re-tin the pads, in fact, don't get Lead bearing solder anywhere near the traces on the substrate. The traces and pads on the ceramic substrate are made from Palladium Silver and Lead has an affinity for the silver. If Lead is used, the traces/pads will disappear like magic from the substrate like, poof, gone! I wish you good luck in restoring your module and bringing the alarm watch back to working order. If you are unable to get a surface mount 10Meg resistor a 1/8 watt metal film or carbon will also work. I check this forum several times a week and if you have questions concerning the operation of the alarm module, post them and I will try and provide an answer. Just to let you know that if you are unable to restore your present module and wish to make your newly purchased watch whole again, I still have some "New Old Stock" alarm modules in my stock from my Frontier days of the "70's, unfortunately I have no battery clips for same.

Ole Joe

[retroleds]

The value of that resistor is 10 Meg Ohms. It is used as a bias resistor between the input/output of the oscillator amplifier to set the threshold of the amplifier to approximately 1/2 the total battery voltage. If you replace this resistor, make sure you DO NOT use a Lead bearing solder to remount it or re-tin the pads, in fact, don't get Lead bearing solder anywhere near the traces on the substrate. The traces and pads on the ceramic substrate are made from Palladium Silver and Lead has an affinity for the silver. If Lead is used, the traces/pads will disappear like magic from the substrate like, poof, gone! I wish you good luck in restoring your module and bringing the alarm watch back to working order. If you are unable to get a surface mount 10Meg resistor a 1/8 watt metal film or carbon will also work. I check this forum several times a week and if you have questions concerning the operation of the alarm module, post them and I will try and provide an answer. Just to let you know that if you are unable to restore your present module and wish to make your newly purchased watch whole again, I still have some "New Old Stock" alarm modules in my stock from my Frontier days of the "70's, unfortunately I have no battery clips for same.

Ole Joe

I always use silver-bearing solder (don't keep any regular stuff in my work area). . . . seems to sidestep the problem completely. I guess the lead has already sopped up enough silver that it can't react further. idk.
Costs a few pennies more, melts at a lower temp, flows beautifully,better physical strength. I have an unfortunate number of those clips with no movement :)