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Yaesu FT-101E no transmit, no i.c.
- Thread starter Champo
- Start date
The ALC meter is a guide to how hard the driver tube is pushing the final tubes.
Lazy ALC deflection to the left may be a weak driver tube. May be weak drive level feeding INTO the driver tube. Full drive to the finals usually pushes the needle most of the way to the left with full mike gain. In this radio, ALC works only for sideband voice. Doesn't work in Tune mode.
If the preselect knob shows a peak S-meter reading in receive mode at a separate spot from where it peaks on transmit, this means the alignment is holding the radio back. Doesn't tell you how much.
Peak receiver signal should occur at the exact, same spot on the preselect knob where transmit power shows its peak. If transmit and receive each show a peak at a separate knob position, the radio is out of alignment. Maybe not by much, but enough to affect performance.
73
Lazy ALC deflection to the left may be a weak driver tube. May be weak drive level feeding INTO the driver tube. Full drive to the finals usually pushes the needle most of the way to the left with full mike gain. In this radio, ALC works only for sideband voice. Doesn't work in Tune mode.
If the preselect knob shows a peak S-meter reading in receive mode at a separate spot from where it peaks on transmit, this means the alignment is holding the radio back. Doesn't tell you how much.
Peak receiver signal should occur at the exact, same spot on the preselect knob where transmit power shows its peak. If transmit and receive each show a peak at a separate knob position, the radio is out of alignment. Maybe not by much, but enough to affect performance.
73
I'll have to confirm tomorrow if they are in the same spot. I think they are but if they aren't it is really, really, really close. Yeah ALC is one of those obscurities I need to better familiarize myself with. It does a quick and complete deflection when checked during tune up. I can't say much beyond that. This might be a dumb question but do new tubes, as in new to this radio, need a burn in time? The other question I guess would be is that neutralization cap mod for domestic tubes necessary? Could neutralization be an issue? I'm not sure why it wouldn't load earlier this afternoon but then did this evening. Ran fine for 2 hours this evening so we'll see what happens come tomorrow. Perplexing to say the least.
On a completely different topic, is the tuning process necessary each time the radio is turned on even if the same band, frequency, antenna etc. is being used? I've been going through the tune up and receive procedure everytime I turn it on.
On a completely different topic, is the tuning process necessary each time the radio is turned on even if the same band, frequency, antenna etc. is being used? I've been going through the tune up and receive procedure everytime I turn it on.
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Neutralization? A veritable rabbit hole, if you believe the lamentations of the last 50 years of FT101 owners.
Quick way to tell if it's right. Using the "Tune" carrier, turned full up, peak all three for max.
Give it a moment to breathe, and then transmit while gently rocking the Plate Tune.
The wattmeter peak and the "dip" in the IC reading should coincide at the same position of the Plate Tune knob.
In real life, they may only be close. And if the power peaks clearly at a spot on the knob different from where the dip is seen, the radio is not neutral.
I should write up what to do next if it's out of whack. But not today.
73
Quick way to tell if it's right. Using the "Tune" carrier, turned full up, peak all three for max.
Give it a moment to breathe, and then transmit while gently rocking the Plate Tune.
The wattmeter peak and the "dip" in the IC reading should coincide at the same position of the Plate Tune knob.
In real life, they may only be close. And if the power peaks clearly at a spot on the knob different from where the dip is seen, the radio is not neutral.
I should write up what to do next if it's out of whack. But not today.
73
Awesome! I can handle that. I'll report back with my findings. Hopefully it'll be this evening if can squeeze in some time.
I had a bit of time so I tried going through the tuning process again but before I did I keyed up to see if everything was the same as last night. It keyed up but the i.c. was off in relation to yesterday (higher). Power output was also higher than yesterday. I then tried going through the tuning process but couldn't get the plate to load. I turned off the heaters and let the tubes cool. I then turned off the radio and let it sit for 30 min. I turned it back on and attempted the tuning process but again I couldn't load properly. I'll try pulling all three tubes again and swapping them like yesterday to see if that changes anything. That's what I did yesterday. It seemed that pulling the driver tube may have been what did it but that could be purely coincidental. Would some DeoxIT in the pin sockets be a wise idea? The i.c. also doesn't remain consistent. Anytime the radio is turned off and then back on later the bias value will be different (could be higher, could be lower) but it never stays right at .06. I was informed that it should. It will remain at .06 through the operation session though. Anyways, that's my story.
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Clean the sockets with deoxit. Clean all the controls. Clean the vr's on the power supply board. Then set the voltage.
First thing I do is a complete cleaning of all controls and VR's. Then Blow out the chassis. Then recap and change the resistors on the power supply board. Then set the voltage and current. Then try it out. If I have problems after all that it's easier to troubleshoot. The driver tube does not need to be a Japan made one. Though I do have some NOS ones from Japan I have had good luck with all I have tried.
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I appreciate the reply. It's funny that you mention the driver tube. I just got off the phone with WA0CBW (ARRL Technical Coordinator for Kansas) and he's confident (after tuning through it over the phone) that the driver tube is the cause. Not that something else couldn't also be wrong but he suspects the driver. You two are on the same brain wave lol. Ironically enough I ordered a NOS (tested) driver a few days ago as a precautionary measure since the driver was original (intuition? J/K!). It should be here early next week. Fingers crossed that that is all it is. The long term plan, presuming this doesn't become a money pit, is to recap it but I need it to work reliably for more than a day before I proceed down that road. I gave the bias knob a good cleaning but I was afraid to attack any of the other adjustments for fear of not being able to get them set correctly again. All of the switches, waffers etc got a good cleaning and I reseated each of the boards.
That radio is pretty simple. Should not be a money pit. Most expensive thing is the finals. Once you get it good just recap and replace the resistors on the power supply board. Don't worry about all the other boards unless you have a problem in the area that a specific board controls. Believe it or not the Japanese caps on those boards were extremely high quality.
And to think. A tube tester can save hours of head scratching.
The 12BY7A driver tube is a really high-gain animal. Any time the tester reads low on one of these, we know it won't perform in a FT101 like it should.
Has the last few decades of black schmoo been removed from all the sections of the band switch? If not, this can introduce unpredictable behavior.
73
The 12BY7A driver tube is a really high-gain animal. Any time the tester reads low on one of these, we know it won't perform in a FT101 like it should.
Has the last few decades of black schmoo been removed from all the sections of the band switch? If not, this can introduce unpredictable behavior.
73
It was surprisingly clean. It did get a thourough dousing in DeoxIT and many, many, many rotations of the switch. I'll double check it though to make sure I didn't miss anything. I would kill for access to a tube tester. Unfortunately I haven't been able to locate someone with one nearby. There is a guy in a neighboring city that I came across on Ebay that sells tested tubes. I've contemplated shooting him a message to see what he would charge to test some tubes but I have a feeling it wouldn't be worth his time. I have some tubes out of a Sonar FS-23 that I've been recapping and replacing resistors in that could stand to be tested.
Even though I have several tube testers I still find the best test is in circuit and testing in the radio I will be using the tube for. I have had tubes that read perfect that did not perform as good as a tube that read 70% in certain areas. A shorted tube on the other hand that's a different story.