Re: [Drakelist] TR-7 TR Relay
Pete -
Why are you replacing the Varley?
I would suggest verifying that the terminal layout is identical, it 'almost'
certainly is.
Rather than the 'W' contact material, I would suggest the 'Y' used by Drake. The 'W' material
(Silver Cadmium Oxide) is rated at 500 mA _minimum_, 7.5A maximum. Obviously MOST of the contacts
in the TR-7 relay are carrying considerably less than 500 mA. The 'Y' material (Fine Silver) is
rated at 100 mA minimum and 3A maximum.
Lower current capabilities require bifurcated contacts, rather than the simple button contacts. 'Z'
material is Fine Silver, but with bifurcated contacts and is rated at 1mA to 2A.
Dry circuit contacts ('P') are gold over silver, bifurcated, and are rated for 0mA - 3A. These
are more expensive and harder to find. The gold would probably burn off after the first VOX, at
least on the antenna contacts.
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
Pete Juliano wrote:
I am looking for an alternate to the TR relay in my TR-7 and wonder if anyone has suggested
substitutes. As best as I can tell the OEM part was supplied by Varley and the P/N is a VP4CAB/12
V185.
The Varleys are made in the UK. I believe this relay is a General Purpose type relay classed as 4
Changeovers, DIN21, USA C. I could tell exactly but I think the contacts maybe 5 amps or less.
That said I did look at the PB relays and RF Parts sells the R10E1W4V185 for about $20. The
contact arrangement is the same, the coil resistance is the same (185 Ohms) and the relay contacts
at 7.5 amps should handle 150 watts.
The mating socket is the 27E126 available from Mouser as is the hold down spring which is the
20C250. This is the same socket and spring that are used for the substitute T4XB plug in TR Relay.
So am I off in the weeds with the PB substitute and has someone identified an exact sub for the
Varley relay.
73's
Pete N6QW
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[Drakelist] Question about dial darkening
I see there may be someone that has removed the dark brown discoloration from a Drake dial. (I have about 3 Drakes with this problem.) Can anyone lend specific light on how to accomplish this without destroying the dial? THANKS! Allen, W0OUU ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Question about dial darkening
If the dark brown is due to UV exposure, there is no way to restore it since it is throughout the plastic. If it is smoker's grunge, then a variety of cleaners can be used BUT make sure they are NON-abrasive and don't due other damage. I use some cleaner for delicate plastic, electronic equipment, etc. that is made by GC. As with any cleaner, proceed with caution and test a hidden area to see if the cleaner is compatible with the plastic. Might have some added tips in the WB4HFN Drake website or Electric Radio magazine. 73, Evan, K9SQG -Original Message- From: Allen Bush adb66...@yahoo.com To: drakelist drakelist@zerobeat.net Sent: Mon, Jan 16, 2012 7:14 am Subject: [Drakelist] Question about dial darkening I see there may be someone that has removed the dark brown discoloration from a Drake dial. (I have about 3 Drakes with this problem.) Can anyone lend specific light on how to accomplish this without destroying the dial? THANKS! Allen, W0OUU ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] TR-7 Relay
Pete - Couple of factors make this relay suitable... 1. 150W into 50 ohms is only about 1.7A, so no problem there. 2. The Drake 'yank-in' VOX system 'probably' closes the contacts before any RF gets to them, limiting the 'make'. 3. The more damaging 'break' comes after the RF is long gone thanks to VOX delay. Unless someone is running one of the 'chirp-chirp' style digital signals and has the VOX to minimum. The Y contacts are rated at 100 mA minimum, 2A typical, and 3A 'maximum'. I have yet to come across damaged antenna switching contacts in any Drake transmitter that hadn't been abused. (Transmitting for 'a while' into a wrong or NO antenna, with multiple key and unkey cycles.) The '+13.6 VDC' Transmit bus drives several 10 uF tantalum caps on various boards. Dunno if that is causing relay problems or not. Also no idea how much current those contacts are having to handle. 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 Pete Juliano wrote: Hi Garey, Thanks for your response -- as usual really excellent information. I will need to do more research as the Y types. The ones in the Y series that RF Parts have the contacts are only good for 2 amps -- I would think you need more than a 2 amp contact rating to handle the RF which is switched through that relay. But then again --duty cycle versus constant current. As to why the replacing the Varley . I am tracking down an intermittent problem with my TR-7 and in the event the TR relay is the problem then I would be looking for a replacement or substitute. The problem is that every so often when you key the microphone or hit the key you will hear the relay click but no output. Now the person I bought the TR-7 from said he had that problem --and in fact thought it was a problem on the pre--driver board and replaced the MPS-H20 -- only that was not the problem as occasionally there would not be 13.6 VDC applied to the pre-driver coincident with the non-keying. The 13.6 VDC is routed through that relay via pins 14, 15 and 16. So he thought it was crudded contacts on the socket and so he pulled the relay and sprayed de-oxit in the relay socket and that seemed to solved the problem. I don't believe he opened up the relay to look at the individual contacts. I searched the archives and saw a related problem which was the VCO going out of lock -- but I haven't been specifically looking for that condition. I thought I would start with the easier to work issues (clean a relay versus align a VCO) I haven't opened the TR-7 as yet and pulled the relay -- but that is the next step. My research was to see what do I do next in the event that is the problem. Thanks again for the excellent information. 73's Pete N6QW ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] Invitation to connect on LinkedIn
LinkedIn Giuseppe Rubini requested to add you as a connection on LinkedIn: -- Phillip, I'd like to add you to my professional network on LinkedIn. - Giuseppe Accept invitation from Giuseppe Rubini http://www.linkedin.com/e/8c5iaq-gxi1yskq-42/zScuIwKarYGZzAhIOPfzrGQZrOVCFmrb_7P/blk/I334100134_20/1BpC5vrmRLoRZcjkkZt5YCpnlOt3RApnhMpmdzgmhxrSNBszYMcBYQcP4Mc34QcPd9bQFFs2Rvj6lQbPASczcTdz4QdjkLrCBxbOYWrSlI/EML_comm_afe/?hs=falsetok=1dc7UJDYMnql41 View invitation from Giuseppe Rubini http://www.linkedin.com/e/8c5iaq-gxi1yskq-42/zScuIwKarYGZzAhIOPfzrGQZrOVCFmrb_7P/blk/I334100134_20/30OnPgPcj0McjgPcQALqnpPbOYWrSlI/svi/?hs=falsetok=0ZUlYNcL8nql41 -- Why might connecting with Giuseppe Rubini be a good idea? Giuseppe Rubini's connections could be useful to you: After accepting Giuseppe Rubini's invitation, check Giuseppe Rubini's connections to see who else you may know and who you might want an introduction to. Building these connections can create opportunities in the future. -- (c) 2011, LinkedIn Corporation___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] TR-7 Relay
Lee - I am receiving no emails from you. We must have a spam filter that has popped up between us. Try k4...@verizon.net 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 K9sqg wrote: Hi Evan, Lee here... Can you contact Garey Barrell K4OAH and see if he is getting e-mails from me through the list AND direct... Seems like I have sent him several e-mails in the last few days with no response... Thanks, Lee, KC9CDT ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] Communications?
Lee - I am receiving your posts to the Drakelist just fine, just nothing direct. Evan - Spoke too soon. This message was bounced from Drakelist by something called SPAMCANNIBAL... Good grief 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 ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] R-4B...need schematic for S/N 9129
Anyone ... Need a schematic for Drake R-4B S/N 9129. I have a R-4A S/N 5900 R-4B S/N 9129 R-4B S/N 10851 The R-4A and early R-4B both exibit the issue of clicking on loud signal with NB off if you tune the opposite SB (Or a loud sig. next to the one you want does that for you) I can not test the R-4B later as I have the PTO out right now trying to brighten up the yellowed dial. BUT the late R-4B which matches the Schematic I have show the V9 grid bias not being driven by AVC...and that RCV is wired that way. Garey, since you haven't got my direct e-mails (spam issue) I also need to know if that R-4B S/N 9129 is covered in your CD (Schematic, photos etc) For now I need just the schematic...but I want the CD as well if it covers this unit. I would like to develop a MOD to install to fix this issue on a R-4A and early R-4B 73, Lee Lee Simmonds Summit DCS LLC 260-799-4077 Office 260-403-6936 Cell ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] R-4A / R-4B AVC/NB problem.
Lee - It looks like the internet robots aren't going to allow us to converse directly. Hopefully you are getting list mail ok.. You made a statement some time back that you had the same problem with BOTH an R-4A AND an R-4B. The point I have been trying to get across for the last week or so is that there were considerable changes to the grid circuit of the NB Amplifier, including removing it from the AVC bus, _AFTER_ s/n 10501. The first 3000 R-4Bs were exactly the same as the R-4A in this area. The latest schematic for the R-4B that is on the CD is the one in the back of the R-4B Original manual. The two earlier versions are in the MISC directory of the CD. -- 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 ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
