EMRFD Message Archive 9937

Message	Date	From	Subject
9937	2014-04-21 22:18:17	rcbuckiii	Best way to cut open crystal filter?
This is off topic but maybe someone has experience with this procedure. I have a Kenwood YG-88C crystal filter that was in my TS-820. The filter went bad and I replaced it. The center frequency is supposed to be 8.8307 MHz. I swept it with my spectrum analyzer and the peak passband frequency is 8.830463 MHz with -14.56 dB loss. Sweeping the replacement filter shows a peak at 8.830774 MHz with -9.3 dB loss which would be normal for this filter. Now I want to cut the filter open without damaging the components inside if possible. Has anyone ever cut a commercial crystal filter open? I'm thinking that it might be possible to cut around the bottom where the case is welded to the base. This is more for curiosity than anything. I would like to see what is inside the filter. My guess is that one or more of the tuning capacitors inside has gone bad causing the filter to fail. If nothing is damaged when cutting it open it might also be possible to repair it. Ray AB7HE
9938	2014-04-22 03:54:06	kerrypwr	Re: Best way to cut open crystal filter?
This will be a monolithic crystal filter, not the lattice type with coupling capacitors that we build with discrete crystals; I doubt that it is repairable. If I wished to open it for curiosity's sake, I would mount it on the milling-machine table in its upright position and run a slitting saw around the case just a little up from the base. A similar result could be obtained with a fine-tooth hacksaw or jeweller's saw and some delicacy. Kerry VK2TIL.
9939	2014-04-22 08:03:57	rcbuckiii	Re: Best way to cut open crystal filter?
Thanks Kerry. I don't have a milling machine. I will mount it in a vise and try to use my Dremel cutting wheel to get into the case. It should be interesting to see what is inside. Ray AB7HE
9940	2014-04-22 08:33:17	dx11	Re: Best way to cut open crystal filter?
Hello Ray, Would it be possible for you to make some pictures before and after and publish them in the files section? We might all be able to learn from it.   Cor PA4Q Thanks Kerry. I don't have a milling machine. I will mount it in a vise and try to use my Dremel cutting wheel to get into the case. It should be interesting to see what is inside. Ray AB7HE
9941	2014-04-22 08:34:13	Sandeep Lohia	Re: Best way to cut open crystal filter?
On 22/04/2014, rcbuckiii@yahoo.com <rcbuckiii@yahoo.com> wrote: > Thanks Kerry. I don't have a milling machine. I will mount it in a vise and > try to use my Dremel cutting wheel to get into the case. > > It should be interesting to see what is inside. > > Ray > AB7HE don't use any type of revolving wheel, which might generate shock-wave... internal white XTAL film is very fragile... (trying this method I destroyed previously) rather use your hand to hold, & use a small angled sharp component's lead cutter, as to cut off outer enclosure. ( easy & successful ) be careful, even if it fall from your hand, internal film might damage, unless otherwise it's spring loaded... (mailed 4rm mobile) -- Please encourage recycling, reuse or repairing of E-waste. ░7░3░ ░d░e░ ░V░U░3░S░X░T░
9942	2014-04-22 08:50:13	Sandeep Lohia	Re: Best way to cut open crystal filter?
sorry, I meant to say abt XTAL & not filter... -- Please encourage recycling, reuse or repairing of E-waste. ░7░3░ ░d░e░ ░V░U░3░S░X░T░