The last source I had for cores was Ocean State Electronics. (800-866-6626) Their stock number FT82-75 is about 1 inch is diameter and works with 14 turns of small wire on both primary and secondary, or wind a couple more on the secondary to boost the voltage. Both windings should have about 500uH to 550uH inductance to match the impedance of the heaters. Other cores that look the same may not have the same permeability. They only like to sell in large quanities (about 50 cores) so 2 or 3 shops could share an order. This info is about 5 years old so don't know if they are still in business. John Mielke. TomLee wrote: > It is a good idea Gary.I saw a lot amplifier boards use donut core. Any way > the PTV wsa fixed last night. and it works just fine by windding around > flyback 3 turns the voltage > is very close to the orgiginal 5Vac. one more thing. I want one pc mother > board (p4) > Can I pay by credit card.Or you only accept money order.(international) > Dang t8872695@xxxxxxxxxxxxx > -----Original Message----- > From: Gary McCartney <number63@xxxxxxxxxxxxx> > To: techassist@xxxxxxxxxxxxx <techassist@xxxxxxxxxxxxx> > Date: Wednesday, October 16, 2002 12:30 PM > Subject: [TechAssist] Re: MIT PTV VS-5007R > > > >>You can also use a torroid donut core and wrap a few turns around it on >>one side, and on the opposite side wrap the same number of turns around >>it. Then insert the newly made transformer into the line going to the >>heater pins on the CRT socket. Only problem is where to get the torroids >>from. Does anyone presently have a supplier for these? >> >> >>Gary McCartney >> >>McCartney Electronics >>7134 Fife Rd, RR 7 >>Guelph Ontario Canada N1H 6J4 >>Fax: (519)821-1530 >>email: number63 (at) inetsonic.com >> >> >> >> >>Kevin wrote: >> >>>That is true. I never thought of the flyback arcing out. I would not >>>wrap the flyback if it was a Mitsubishi. However, I was just thinking >>>if the wire was insulated would the arc burn through the insulator? The >>>arc should go to any exposed metal frame first, shouldn't it? Also what >>>type of isolation transformer do you use? I use a 120 V AC to 6.3 V AC >>>transformer which requires the turn-on relay in the TV to turn the >>>heater on and off. TV's that don't have this type of turn-on (Zenith >>>and RCA as examples) would have to use the wire-wrap. >>> >>>Kevin Wilks >>>Kevin's TV & Video Repair >>>Penticton BC Canada >>>kevinstv@xxxxxxx >>> >>>-----Original Message----- >>>From: techassist-bounce@xxxxxxxxxxxxx >>>[mailto:techassist-bounce@xxxxxxxxxxxxx] On Behalf Of Leonard G. >>>Caillouet >>>Sent: Wednesday, October 16, 2002 6:47 AM >>>To: techassist@xxxxxxxxxxxxx >>>Subject: [TechAssist] Re: MIT PTV VS-5007R >>> >>>Just common sense to me. How many FBTs have you seen fail by arcing >>>out. >>>They rarely short internally to the filament winding but if you have a >>>winding around the outside of the transformer and it decides to arc, >>>where >>>do you think it might go first? Installing the isolation transformer >>>seems >>>safer to me and can be done from the front of most sets. It's only a >>>few >>>bucks for the part. Why not make a profit on the part and use the safer >>>method? Also on a three tube projector you are likely to end up with >>>different filament voltages by winding the FBT. For me it's as much of >>>a >>>no-brainer as winding the flyback is for the guys that do it that way. >>>Just >>>a difference in philosophy... >>> >>>Leonard G. Caillouet >>>Service Manager >>>Electronics World >>>Gainesville, FL >>>352-332-5608 >>>352-332-5668 (fax) >>> >>>----- Original Message ----- >>>From: "Kevin" <kevinstv@xxxxxxx> >>>To: <techassist@xxxxxxxxxxxxx> >>>Sent: Thursday, October 17, 2002 4:05 AM >>>Subject: [TechAssist] Re: MIT PTV VS-5007R >>> >>> >>>>Leonard, >>>> >>>>Why do you find that winding the flyback an 'unnecessary risk and more >>>>trouble'? Thanks for your reply. >>>> >>>>Kevin Wilks >>>>Kevin's TV & Video Repair >>>>Penticton BC Canada >>>>kevinstv@xxxxxxx >>>> >>>>-----Original Message----- >>>>From: techassist-bounce@xxxxxxxxxxxxx >>>>[mailto:techassist-bounce@xxxxxxxxxxxxx] On Behalf Of Leonard G. >>>>Caillouet >>>>Sent: Tuesday, October 15, 2002 7:16 AM >>>>To: techassist@xxxxxxxxxxxxx >>>>Subject: [TechAssist] Re: MIT PTV VS-5007R >>>> >>>> >>>>Use a CRT isolation transformer. They are inexpensive and available >>>>from >>>>most suppliers. While there is generally no problem with winding the >>>>FBT, I >>>>find it to be an unnecessary risk and more trouble. Also, on a >>>>projection >>>>set, you may want to verify the voltage at the filaments to assure >>> >>>that >>> >>>>it >>>>is the same on all the CRTs. The filaments are in parallel in this >>> >>>set >>> >>>>so >>>>there is no need to isolate all three tubes, and the voltage should >>>>remain >>>>pretty close if you use the 1-1 winding on the transformer, but I'd >>>>check it >>>>anyway. >>>> >>>>Leonard G. Caillouet >>>>Service Manager >>>>Electronics World >>>>Gainesville, FL >>>>352-332-5608 >>>>352-332-5668 (fax) >>>> >>>>----- Original Message ----- >>>>From: "tomlee" <t8872695@xxxxxxxxxxxxx> >>>>To: <techassist@xxxxxxxxxxxxx> >>>>Sent: Monday, October 14, 2002 11:08 PM >>>>Subject: [TechAssist] MIT PTV VS-5007R >>>> >>>> >>>> >>>>>Hello members. >>>>>I am working with MIT VS-5007R PTV . red gun K short to heater .any >>>> >>>>body >>>>know how to bypass this or anyway to fix this.Should I use crt short >>>>remove? >>>>I have B&K470 but I do not have crt adapter .In the direct view tv I >>> >>>can >>> >>>>make isolator heater.But this is DC heater volatge with 3guns in >>> >>>series >>> >>>>connection.Any inputs >>>> >>>>>is appriciated. >>>>>DANG >>>>>TD electronics >>>>>18546 sherman way >>>>>reseda ca 91335 >>>>> >>>>>------------------------------------------ >>>>>To REMOVE your email address, click here: >>>>> http://www.tech-assist.org/unsubb.html >>>>>To CHANGE your email address, click here: >>>>> http://www.techassist.net/forms/change.html >>>>>------------------------------------------ >>>>>***NEW*** Tips Added Instantly!!!*** >>>>>Submit Repair Tips here: >>>>>http://www.tech-assist.org/secure/tip/ >>>> >>>> >>>>------------------------------------------ >>>>To REMOVE your email address, click here: >>>> http://www.tech-assist.org/unsubb.html >>>>To CHANGE your email address, click here: >>>> http://www.techassist.net/forms/change.html >>>>------------------------------------------ >>>>***NEW*** Tips Added Instantly!!!*** >>>>Submit Repair Tips here: >>>>http://www.tech-assist.org/secure/tip/ >>>> >>>>------------------------------------------ >>>>To REMOVE your email address, click here: >>>> http://www.tech-assist.org/unsubb.html >>>>To CHANGE your email address, click here: >>>> http://www.techassist.net/forms/change.html >>>>------------------------------------------ >>>>***NEW*** Tips Added Instantly!!!*** >>>>Submit Repair Tips here: >>>>http://www.tech-assist.org/secure/tip/ >>> >>>------------------------------------------ >>>To REMOVE your email address, click here: >>> http://www.tech-assist.org/unsubb.html >>>To CHANGE your email address, click here: >>> http://www.techassist.net/forms/change.html >>>------------------------------------------ >>>***NEW*** Tips Added Instantly!!!*** >>>Submit Repair Tips here: >>>http://www.tech-assist.org/secure/tip/ >>> >>>------------------------------------------ >>>To REMOVE your email address, click here: >>> http://www.tech-assist.org/unsubb.html >>>To CHANGE your email address, click here: >>> http://www.techassist.net/forms/change.html >>>------------------------------------------ >>>***NEW*** Tips Added Instantly!!!*** >>>Submit Repair Tips here: >>>http://www.tech-assist.org/secure/tip/ >> >>-- >> >>------------------------------------------ >>To REMOVE your email address, click here: >> http://www.tech-assist.org/unsubb.html >>To CHANGE your email address, click here: >> http://www.techassist.net/forms/change.html >>------------------------------------------ >>***NEW*** Tips Added Instantly!!!*** >>Submit Repair Tips here: >>http://www.tech-assist.org/secure/tip/ > > > ------------------------------------------ > To REMOVE your email address, click here: > http://www.tech-assist.org/unsubb.html > To CHANGE your email address, click here: > http://www.techassist.net/forms/change.html > ------------------------------------------ > ***NEW*** Tips Added Instantly!!!*** > Submit Repair Tips here: > http://www.tech-assist.org/secure/tip/ > > -- John Mielke Main TV Longmont,Co 303 776 6955 maintv2002@xxxxxxxxxxxxx ------------------------------------------ To REMOVE your email address, click here: http://www.tech-assist.org/unsubb.html To CHANGE your email address, click here: http://www.techassist.net/forms/change.html ------------------------------------------ ***NEW*** Tips Added Instantly!!!*** Submit Repair Tips here: http://www.tech-assist.org/secure/tip/