Hi Guys, Well, to-day I plan to "snip" that white tubular capacitor out of my PTO, & see what might happen...
I'll note the frequency on my receiver AND the PTO before doing this, as the frequency from the PTO climbs some 100-KHz in the absence of its "can": I'll then, probably, temporarily install a small air trimmer in place of the tubular cap, & play with the settings until the frequency might return to where it originally was, in the interest of linearity. I can then sub the trimmer with a fixed s.m. capacitor, perhaps in parallel with a small ceramic trimmer. Stay tuned---and wish me luck! ~73~ de Eddy VE3CUI - VE3XZ ************************************************************************************************************************* On 2011-09-22, at 3:36 PM, Garey Barrell wrote: > Yes, that is a 'trim' cap and should be less than 10 pF or so. It's not > likely to have much effect on the stability of the oscillator. More likely > are the caps on the 'other' side of the board, shown further down, the two > brown tubular caps to the left of the Diode D13 are 45 pF each. That's > probably a 'C-Line' Version 7 PTO. Probably a result of either a better buy > on two 45 pF caps over a single 90 pF, or a mechanical rearrangement of the > board layout. Those two caps are the most critical as far as stability of > the oscillator is concerned. > > 73, Garey - K4OAH > Glen Allen, VA > > Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line > and TR-4/C Service Supplement CDs > <www.k4oah.com> > > > Eddy Swynar wrote: >> Hi Guys, >> >> For a look-see at the suspect tubular capacitor that I am referring to in my >> T-4X PTO, go to this website: >> >> http://www.wb4hfn.com/DRAKE/DrakeArticles/TechTips/PTO-Repair.htm >> >> Scroll down half the page to where you see the heading "ELECTRICAL >> FAILURES": the photograph with the arrowed inscription marked "solder point" >> is immediately left of the white tubular capacitor that I am referring to... >> >> ~73~ de Eddy VE3CUI - VE3XZ _______________________________________________ Drakelist mailing list [email protected] http://mailman.zerobeat.net/mailman/listinfo/drakelist
