Update on my TPN1110 Micor power supply repair. It was nice of Motorola to have screw mountings on the CR1, CR2, CR3, CR4. Which made it easy to to check these. There is a forward to back resistance on all four diodes. How close should the resistance be? One is about 100 ohms less than the other three?
I noticed CR1, & CR2, turn on the aluminum housing. Upon checking C1. Unlike the TPN1110B schematic I have, which shows one C1. In my power supply, C1 has two capacitors (back to back), with three wires connected to the secondary. Using my old analog meter there is a charge between the two capacitor terminals. Although, I was expecting a charge on both sides, to the ground terminal, & in both directions. Which was not the case. There was a resistance on the secondary. I did notice a arch spot on a ground wire which was in close to the L1, or L2 wires. There is no noted ohms on this ground wire to the pin head arch spot. I will position the ground wire away from these other larger wires. Now to determine the proper part(s) to replace. >From my limited knowledge of this power supply. I will work on attempting to >get replacements for C1 & CR1, CR2, CR3, CR4. Any inputs are welcome. 73's, Jim Kh6jkg. ----- Original Message----- From: [email protected] To: [email protected] Sent: Tue, 24 Feb 2009 10:10 am Subject: [Repeater-Builder] Motorola Micor Power Supply - TPN1110B Thanks Eric for the correction on the model #. Why would CR1,CR2 , or CR3, CR4 short? I would think they would open, or one/some would open, not short. I will call our local Mot. Repair to locate the these diodes. I guess I could work on separate the secondary from C1, to check if C1 is shorted. Thanks, 73’s, Jim Kh6jkg. ’s, Jim Kh6jkg. Jim, It took me a while to figure out what you have. TLN5123B is not the model of the power supply; it is the part number of the Chassis and Hardware Kit in a TPN1110B Power Supply. If your power supply blows the 10 ampere fuse F1 with no load connected to TB1 and both F2 and F3 pulled, you have greatly narrowed the possibilities. The most likely candidates, in order, are shorted CR1 or CR2, then shorted CR3 or CR4, and finally a shorted C1. If capacitor C1 is either open or shorted, the ferroresonant transformer cannot regulate properly. Note that more than 600 VAC appears across C1 during normal operation, and you must replace this capacitor with a similar unit designed for this application. 73, Eric Lemmon WB6FLY -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Monday, February 23, 2009 8:36 PM To: [email protected] Subject: [Repeater-Builder] Motorola Micor Power Supply - TLN5123B I have a Micor power supply, that stopped working. I removed the power supply, currently no load on the bench. Back plane fuse - OK F3 - 13.8v fuse - OK, 0vac, Voltage 4.7vdc before F3 F2 - 9.6v fuse -=2 0OK, 0vac, Voltage 2.2vdc before F2 F1 10 amp. opens if left powered on. I am able to measure the above voltages before F1 opens. With no AC power, I measured the resistance across TB1, (After temporally shorting to ground to remove any stored voltage, and opening F2, & F3.), 15.3 ohms. There are not many components before F2, and F3. I guess the next components to check are CR1, CR2, CR3, CR4. Although, I have not seen many power supplies with C1 across one of the secondary, like Motorola P.S. It would be best to replace all four. Please send me your input, on the likely faulty component(s) to check. Thanks for your emails. 73's, Jim Kh6jkg. -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Monday, February 23, 2009 8:36 PM To: [email protected] Subject: [Repeater-Builder] Motorola Micor Power Supply - TLN5123B I have a Micor power supply, that stopped working. I removed the power supply, currently no load on the bench. Back plane fuse - OK F3 - 13.8v fuse - OK, 0vac, Voltage 4.7vdc before F3 F2 - 9.6v fuse - OK, 0vac, Voltage 2.2vdc before F2 F1 10 amp. opens if left powered on. I am able to measure the above voltages before F1 opens. With no AC power, I measured the resistance across TB1, (After temporally shorting to ground to remove any stored voltage, and opening F2, & F3.), 15.3 ohms. There are not many components before F2, and F3. I guess the next components to check are CR1, CR2, CR3, CR4. Although, I have not seen many power supplies with C1 across one of the secondary, like Motorola P.S. It would be best to replace all four. Please send me your input, on the likely faulty component(s) to check. Thanks for your emails. 73's, Jim Kh6jkg.
