#31
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Yes the hum is there no matter what the volume level is at even when the volume is turned completely down. and like I said whatever is causing the hum noise is also I'm sure causing the unresponsive tuner issue as well.
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#32
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Quote:
Edit: I checked the diodes and here are my results: Diode 1: 171 118 in reverse Diode 2: 174 119 in reverse I measured the diodes with the radio unplugged and turned off, I'm not sure what the numbers mean but maybe some of you guys on here might be able to interpret the results for me as to whether or not my measurements mean the diodes are good or bad, or whether or not I need to have the radio plugged in and powered on to test more accurately, also the diodes were tested using the diode function on my DMM. Last edited by Captainclock; 05-14-2016 at 05:43 PM. |
#33
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Likely you will need to unsolder one end of each diode to get a good test... should read "OL" in one direction and something around 300 to 700 mv in the other direction (depending on the type of diode).
jr |
#34
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They are of the "top hat" variety of diodes it says on the diode case 1N2859 on both. They're soldered in rather precariously so I may just cut one of the leads and if they test fine I can just solder them back into place.
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#35
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Well I cut one side of each diode out of the circuit and they measured around 600mV for both of them one way and measured "OL" going the other way which means they are working as they should be apparently which means that there must be something else causeing the humming and unresponsive tuner issue besides the diodes.
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Audiokarma |
#36
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#37
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On IC's it may not have used them. They went disco in the
80's IIRC. The way the IF is built I would NOT go there unless needed. If the main filter is not the hum check the outputs next & any transistors direct coupled to them. They will probably get HOT fast. Its probably the transistors mounted on the chassis in round holders. 73 Zeno |
#38
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Well I guess I can forget about working on the tuner board specifically on the vernier tuner mechanism because the screws wont budge and the heads keep wanting to strip out on me whenever I try to remove them, which tells me they used poor quality aluminum screws for that part for some reason, which is odd because the rest of the screws they used were stainless steel screws... Last edited by Captainclock; 05-14-2016 at 09:14 PM. |
#39
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Try a better screwdriver on the tuner screws. Do you have any "Liquid Wrench" ? jr |
#40
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Quote:
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Audiokarma |
#41
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Try a drop of WD40 & let it sit a few days. Also heating them
may work. If the heads are stripped you can grab them with a pair of dikes. Once started they come right out. For small stuff get a set of ISO phillips heads. The jap stuff needs a perfect fit or you cant get them out. They let out a snap then turn OK. KLH will use the US standard like a #2 phillips. Buy highest quality so they fit perfect & dont strip like the screws. 73 Zeno |
#42
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PB Blaster penetrating oil is better than WD-40 at loosening fasteners. If you can grab the head with a vice-grip wrench those are often a bit better at gripping than dikes.
__________________
Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4 |
#43
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Or if they are already too messed up, they can be carefully drilled out. I've had to do that many times over the years.
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