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FT-101e ALC issue

Bob Dostall KF8IY All Messages By This Member #26 I've been troubleshooting an FT-101e with an ALC issue. I get full power out at all times. After about 10 minutes of warmup, the alc fails to deflect much to the left. It works great for a few a minutes. I've checked and replaced as needed all of the components in the alc circuit that feed to the processor board. I disconnected the white wire that feeds the processor board and my -1.2v steadily drops to about -.3v. I don't know where else to look. Would gassy finals cause this? Even though I still get full output power? Any help would be greatly appreciated. Bob KF8IY
kc4umo All Messages By This Member #27 开云体育 Hi Bob, Interesting problem. ?And with full output I do not think the finals would cause that but I have seen strange things before. Really does sound like something in the ALC circuit. Have you checked the ALC control itself? ?I have seen those become intermitted before. ? With that in note I have also seen wiring issues that gives false ALC readings. Remember these were used by many cb’ers. I will pull the notes and see what I can find in the next day or so.? Really sounds like something simple. ? Buddy ? toggle quoted message Show quoted text From: [email protected] <[email protected]> On Behalf Of bobd@... Sent: Monday, June 7, 2021 11:29 AM To: [email protected] Subject: [Yaesu-FT-101] FT-101e ALC issue ? I've been troubleshooting an FT-101e with an ALC issue. I get full power out at all times. After about 10 minutes of warmup, the alc fails to deflect much to the left. It works great for a few a minutes. I've checked and replaced as needed all of the components in the alc circuit that feed to the processor board. I disconnected the white wire that feeds the processor board and my -1.2v steadily drops to about -.3v. I don't know where else to look. Would gassy finals cause this? Even though I still get full output power? Any help would be greatly appreciated. Bob KF8IY
Bob Dostall KF8IY All Messages By This Member #28 Hi Buddy, VR2 on the processor board seems fine. I did find several cold solder joints on the processor board that was causing erratic alc readings when trying to adjust VR2 and also very low output power with the processor turned on. I ended up re-soldering the entire processor board which solved those problems. I've recapped the power supply p.c.b. and replaced the two diodes in the alc circuit underneath the finals. I replaced a bad electrolytic on the screen grid of the driver tube. I've checked every component with my modern component testers and I'm hitting a brick wall now. This was an ebay buy that a local ham purchased. I do a lot of repairs on all sorts of radios for the local guys. I had to do a lot of studying on this radio and am aware of the cb crowd. I would guess that this one was used for the 11m band.? lol.? I'm going to try to keep plugging away today on it. I'll try messing around with the alc control on the processor board again. Thank you for your reply Buddy. Have a good day. Bob Dostall Senior Technician Vasu Communications toggle quoted message Show quoted text On Mon, Jun 7, 2021 at 11:44 PM kc4umo <buddymclawhorn@...> wrote: Hi Bob, Interesting problem.? And with full output I do not think the finals would cause that but I have seen strange things before. Really does sound like something in the ALC circuit. Have you checked the ALC control itself?? I have seen those become intermitted before. ? With that in note I have also seen wiring issues that gives false ALC readings. Remember these were used by many cb’ers. I will pull the notes and see what I can find in the next day or so.? Really sounds like something simple. ? Buddy ? From: [email protected] <[email protected]> On Behalf Of bobd@... Sent: Monday, June 7, 2021 11:29 AM To: [email protected] Subject: [Yaesu-FT-101] FT-101e ALC issue ? I've been troubleshooting an FT-101e with an ALC issue. I get full power out at all times. After about 10 minutes of warmup, the alc fails to deflect much to the left. It works great for a few a minutes. I've checked and replaced as needed all of the components in the alc circuit that feed to the processor board. I disconnected the white wire that feeds the processor board and my -1.2v steadily drops to about -.3v. I don't know where else to look. Would gassy finals cause this? Even though I still get full output power? Any help would be greatly appreciated. Bob KF8IY
Bruce Collins Member Profile All Messages By This Member #29 Have you replaced the 12BY7 with a new one yet? I have found a few times an ALC issue go away for some reason with a new driver tube.?
Bob Dostall KF8IY All Messages By This Member #30 Well Buddy I decided to just replace VR2 ALC pot and VR1 as well on the speech processor board. That seems to have pretty much fixed it. The ALC meter deflection diminishes somewhat after I ran it for an hour, but I still get about a half of a scale of deflection?after an hour. It was never that good before. I did try another driver and same results. I think that I'll consider myself happy at this point. Bob Dostall Senior Technician Vasu Communications toggle quoted message Show quoted text On Tue, Jun 8, 2021 at 1:15 PM Bruce Collins KB0TJ <kb0tj1@...> wrote: Have you replaced the 12BY7 with a new one yet? I have found a few times an ALC issue go away for some reason with a new driver tube.?
Bob Dostall KF8IY All Messages By This Member #31 Hi Buddy, I just wanted to let you know that I replaced the FET Q6 on the processor board also and now the ALC is rock solid. The sad part is that my first instinct was to replace the ALC pot. and Q6 from the start, but I talked myself out of it. Oh well. I do want to thank you for your replies and pointing me back to the right direction. It's much appreciated. Bob Dostall Senior Technician Vasu Communications toggle quoted message Show quoted text On Tue, Jun 8, 2021 at 2:57 PM Bob Dostall KF8IY via <bobd=[email protected]> wrote: Well Buddy I decided to just replace VR2 ALC pot and VR1 as well on the speech processor board. That seems to have pretty much fixed it. The ALC meter deflection diminishes somewhat after I ran it for an hour, but I still get about a half of a scale of deflection?after an hour. It was never that good before. I did try another driver and same results. I think that I'll consider myself happy at this point. Bob Dostall Senior Technician Vasu Communications On Tue, Jun 8, 2021 at 1:15 PM Bruce Collins KB0TJ <kb0tj1@...> wrote: Have you replaced the 12BY7 with a new one yet? I have found a few times an ALC issue go away for some reason with a new driver tube.?
Bruce Collins Member Profile All Messages By This Member #32 VG.? What FET device did you use? toggle quoted message Show quoted text On Thu, Jun 10, 2021 at 9:06 AM Bob Dostall KF8IY <bobd@...> wrote: Hi Buddy, I just wanted to let you know that I replaced the FET Q6 on the processor board also and now the ALC is rock solid. The sad part is that my first instinct was to replace the ALC pot. and Q6 from the start, but I talked myself out of it. Oh well. I do want to thank you for your replies and pointing me back to the right direction. It's much appreciated. Bob Dostall Senior Technician Vasu Communications On Tue, Jun 8, 2021 at 2:57 PM Bob Dostall KF8IY via <bobd=[email protected]> wrote: Well Buddy I decided to just replace VR2 ALC pot and VR1 as well on the speech processor board. That seems to have pretty much fixed it. The ALC meter deflection diminishes somewhat after I ran it for an hour, but I still get about a half of a scale of deflection?after an hour. It was never that good before. I did try another driver and same results. I think that I'll consider myself happy at this point. Bob Dostall Senior Technician Vasu Communications On Tue, Jun 8, 2021 at 1:15 PM Bruce Collins KB0TJ <kb0tj1@...> wrote: Have you replaced the 12BY7 with a new one yet? I have found a few times an ALC issue go away for some reason with a new driver tube.?
Bob Dostall KF8IY All Messages By This Member #33 I used an NTE 312 which I have on hand to fix the Sony icf-2010 receivers. 2sk19gr actually crossed to an NTE 133 which I also have, but the 133 has a different pin assignment. toggle quoted message Show quoted text On Thu, Jun 10, 2021, 12:27 PM Bruce Collins KB0TJ <kb0tj1@...> wrote: VG.? What FET device did you use? On Thu, Jun 10, 2021 at 9:06 AM Bob Dostall KF8IY <bobd@...> wrote: Hi Buddy, I just wanted to let you know that I replaced the FET Q6 on the processor board also and now the ALC is rock solid. The sad part is that my first instinct was to replace the ALC pot. and Q6 from the start, but I talked myself out of it. Oh well. I do want to thank you for your replies and pointing me back to the right direction. It's much appreciated. Bob Dostall Senior Technician Vasu Communications On Tue, Jun 8, 2021 at 2:57 PM Bob Dostall KF8IY via <bobd=[email protected]> wrote: Well Buddy I decided to just replace VR2 ALC pot and VR1 as well on the speech processor board. That seems to have pretty much fixed it. The ALC meter deflection diminishes somewhat after I ran it for an hour, but I still get about a half of a scale of deflection?after an hour. It was never that good before. I did try another driver and same results. I think that I'll consider myself happy at this point. Bob Dostall Senior Technician Vasu Communications On Tue, Jun 8, 2021 at 1:15 PM Bruce Collins KB0TJ <kb0tj1@...> wrote: Have you replaced the 12BY7 with a new one yet? I have found a few times an ALC issue go away for some reason with a new driver tube.?

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