Does anyone know if Mac still has any inventory on these, or if not, where a source might exist? 1000 pF.
Thanks in advance for any information anyone can provide.
Dave
Thanks in advance for any information anyone can provide.
Dave
MR 67 Feed thru Caps
- Thread starter dcgillespie
- Start date
You are going to have to call factory parts.....do you have the part number? Just leave her the part number and be patient, she will call you back. Just remember, she does not think part values, model numbers or function, just the assigned Mac part number. Have that info for her and they are easy to deal with.
C - Thanks for the info. Going the factory parts route then will be an issue, as the Mac Service Manual for the MR 67 only spells out what type of cap the cap is (i.e., feed thru), which I already knew based on seeing the component in the unit itself, and on the symbol used for it on the schematic. At least it gave me the value of the cap, but otherwise, there is no identification number given for any of the feed thru caps in the Mac manual for this unit -- so trying to go the factory parts route may not work. Since the caps are pressed into place, it may be that they are simply considered to be part of the chassis, too.
If the factory can't come through, and there's no other sources for them, I can make my own feed thru type cap, but of course, that won't look original -- but it will make the tuner fully operational again.
Thanks for responding.
Dave
If the factory can't come through, and there's no other sources for them, I can make my own feed thru type cap, but of course, that won't look original -- but it will make the tuner fully operational again.
Thanks for responding.
Dave
Having really only recently obtained a Sound technology 1000 I have been staying away from tuners.
Hopefully Patrice or Terry will see this and jump in with a part they have found to use.
If they do not jump in, PM me and I will see if my last contact in engineering might have a answer....
Hopefully Patrice or Terry will see this and jump in with a part they have found to use.
If they do not jump in, PM me and I will see if my last contact in engineering might have a answer....
I'll wait and see if they do -- otherwise, I appreciate your back channel offer. I use the ST 1000A -- such a wonderful alignment generator!
Thanks again.
Dave
Thanks again.
Dave
clinic-audio
all on YAMAHA untill 1990
Hello Dave
Can you post some picture of this cap ? Is it C76 and C77 just before the MODE SELECTOR ? or C6 , C12 ?
Parts list give many possibilities
Can you post some picture of this cap ? Is it C76 and C77 just before the MODE SELECTOR ? or C6 , C12 ?
Parts list give many possibilities
Thanks for the response. The cap in question is C39 on the McIntosh schematic for the later version of this unit (i.e., that using the dual beam EMM 801 eye tube). The unit I have is the earlier version with a single beam eye tube, so the cap may be designated differently if using the earlier schematic -- but in either case, the cap in question is the feed-thru cap that sends the muting control signal through the partition wall to the gating grid of the final limiter stage, V7.
For reference, I am providing two pics that show not only the cap in question, but others like it used in the design. In the first pic, from left to right, the feed-thru caps shown are C43, C39 (the defective one), C32, and C31.
In reviewing the the realities of replacing the old cap with a new piece, besides being able to find a suitable replacement, then there would be the effort to actually replace the defective cap if a suitable replacement could in fact be found. Since the original piece appears to be glued and pressed into place, I felt that I would do more damage to the unit trying to remove the old cap and install a new one -- even if I remove the partition wall they are installed in to do it -- than pursuing other avenues of repair.
Since the capacitance value of the feed-thru device is quite insignificant to its circuit function in this case, I decided that all things considered, even if a new replacement piece could be found, it would be better to simply work to dig out the old feed-thru piece (leaving its body in place), and then install my own new insulated feed-thru pole. So that's what I did. Once the guts of the old feed-thru terminal were removed, I was then able to use a short piece of #12 ga solid copper wire with its plastic coating still in place in the middle of the wire to act as an insulator where it passes through the body of the cap, insert it through the body of the feed-thru cap, and secure the new terminal in place with a dab of Super Glue. The original leads were then reattached to finish the repair.
The pics below show the results after I made the repair (but before cleanup), but it originally looked just like the other caps called out above on either side of it. The fix completely eliminated the symptoms of the tuner as received, and returned it to fully normal operation. I'm not saying that this repair would work properly in every application (i.e. with the front end RF can for example), but in this case, it works just fine, and while not looking exactly as the original build did, it goes a long way in preserving the internal appearance of the unit with regards to this cap.
BELOW: View of the repaired cap from the IF strip side of the cap. The repaired cap is the one with the black insulation on the terminal where it passes through the body of the cap, and has the yellow bodied cap connected to it.
BELOW: View of the repaired cap from within the interior of the chassis underside. It is the terminal with the Blu/Wht wire attached to it.
I have seen pass-thru caps fail from time to time, and depending on how they fail and where they are located in the circuit, they can produce some goofy symptoms. For anyone else who encounters this type of failure, maybe this approach to repair may be just the ticket.
Dave
For reference, I am providing two pics that show not only the cap in question, but others like it used in the design. In the first pic, from left to right, the feed-thru caps shown are C43, C39 (the defective one), C32, and C31.
In reviewing the the realities of replacing the old cap with a new piece, besides being able to find a suitable replacement, then there would be the effort to actually replace the defective cap if a suitable replacement could in fact be found. Since the original piece appears to be glued and pressed into place, I felt that I would do more damage to the unit trying to remove the old cap and install a new one -- even if I remove the partition wall they are installed in to do it -- than pursuing other avenues of repair.
Since the capacitance value of the feed-thru device is quite insignificant to its circuit function in this case, I decided that all things considered, even if a new replacement piece could be found, it would be better to simply work to dig out the old feed-thru piece (leaving its body in place), and then install my own new insulated feed-thru pole. So that's what I did. Once the guts of the old feed-thru terminal were removed, I was then able to use a short piece of #12 ga solid copper wire with its plastic coating still in place in the middle of the wire to act as an insulator where it passes through the body of the cap, insert it through the body of the feed-thru cap, and secure the new terminal in place with a dab of Super Glue. The original leads were then reattached to finish the repair.
The pics below show the results after I made the repair (but before cleanup), but it originally looked just like the other caps called out above on either side of it. The fix completely eliminated the symptoms of the tuner as received, and returned it to fully normal operation. I'm not saying that this repair would work properly in every application (i.e. with the front end RF can for example), but in this case, it works just fine, and while not looking exactly as the original build did, it goes a long way in preserving the internal appearance of the unit with regards to this cap.
BELOW: View of the repaired cap from the IF strip side of the cap. The repaired cap is the one with the black insulation on the terminal where it passes through the body of the cap, and has the yellow bodied cap connected to it.
BELOW: View of the repaired cap from within the interior of the chassis underside. It is the terminal with the Blu/Wht wire attached to it.
I have seen pass-thru caps fail from time to time, and depending on how they fail and where they are located in the circuit, they can produce some goofy symptoms. For anyone else who encounters this type of failure, maybe this approach to repair may be just the ticket.
Dave
clinic-audio
all on YAMAHA untill 1990
Hello
here is what I found , it is closer to original type and cost less than 2 $ . All the other available type cost much more and are complicate to use at the same place !
https://www.digikey.com/product-det...ents/2461-001-X7V0-102PLF/410-1045-ND/2079619
here is what I found , it is closer to original type and cost less than 2 $ . All the other available type cost much more and are complicate to use at the same place !
https://www.digikey.com/product-det...ents/2461-001-X7V0-102PLF/410-1045-ND/2079619
Thanks so much for your efforts -- I had originally tried Digikey and Mouser as well. The reason I shied away from those components was due to their 100 volt rating. In use, the component is normally subjected to no more than about 25 vdc -- except at turn on, where the voltage is initially closer to 200 volts, a product no doubt of today's higher line voltages, and reinforced by the fact that the selenium B+ rectifiers have previously been bridged with silicon. Over the years, this is no doubt why the original cap failed. Ultimately, I was not able to find a replacement that was the same physical size as the original, the same capacitance, and in at least a 200 volt rating. Admittedly, I didn't spend hours looking, but between not readily finding a suitable part, coupled with the potential damage I felt was possible in removing the old cap, that I went ahead with the fix that I did.
Again, the time you took to investigate obtaining a suitable replacement part is most appreciated!
Dave
Again, the time you took to investigate obtaining a suitable replacement part is most appreciated!
Dave
