Phil -
OK, that is typical for Drake manuals. They did NOT change the "body"
of the manual for every version. You DO have the correct schematic,and
you have "decoded" the schematic correctly. The schematic shows the
correct tube lineup, but the "block" diagram shows the older tubes.
The next version is 28500.
The CDs are described at www.k4oah.com, and are available now. Each CD
includes all 'known' schematic versions. (Eight for the TR-4.)
73, Garey - K4OAH
Walker wrote:
Garey,
Thank you for confirming what revision my unit is built to. I had an
interchange with Mark Nace N5KAE who indicated perhaps I had an early
version of the manual and might find a later one printed. I looked for
anything with a date on my manual and the only things that gave any clue
was a backpanel photo of a unit with serial number 16050 and the
schematic had the number 466827500 on the bottom. I guessed that number
could mean 4/4/68 starting with serial number 27500 (mine is 28142 as
noted below). Apparently you have the secret decoder ring that confirmed
what the drawing number means.
Bob Ladden WW3QB also wrote that you were compiling different versions
of schematics and other information for a service CD. When you're back
to full vim and vigor, I'd appreciate a note from you when that CD is
available for release.
Last summer, I purchased a couple other Drake units, an R-4B S/N 13269,
and a T-4XB S/N 18843, so I could also get on the newer bands with added
crystals vs the TR-4 (I also operate CW and the receiver will be
infinitely better for selectivity compared to the transceiver). The
receiver came with a manual that has schematic number 05076410501, and I
had to buy a manual for the transmitter from a guy in Australia on eBay
that has schematic number 8126916159. Do you have any pearls of wisdom
as to what I might find relative to manual vs hardware differences on
these two units?
It's great you are able to share your knowledge and experience with
others in the Drake community..thank you!
73,
Phil Walker, WA2CLX
Garey Barrell wrote:
Phil
Your unit is built to schematic 27500, and should have 6EJ7, 6BA6, and
6BZ6. Earlier units (27000) had the 12V tubes.
73, Garey - K4OAH
Walker wrote:
I have a TR-4, 1968 manufacture date, serial number 28124. It has
worked well for years, with the last few being dormant as my vertical
took a hit a few winters ago with icing. I've replaced the vertical,
and I'm trying to re-tube the unit. Here is where the confusion arises:
The chassis lettering and schematic for tubes V4, V5, V11 and both
agree and are respectively: 6EJ7, 6BA6, 6BZ6.
Note: the schematic has V5 and V11 with a hand lettered "6" in front
of 6BA6 and 6BZ6 versus all other tubes which have stencil guided
lettering.
The Manual's Voltage Reference chart and Tube List for V4, V5 and V11
are: 6EJ7, 12BA6, 12BZ6
The Manual's Block Diagram shows V4 as 6HS6
I'm not sure what's supposed to be right, though I have a tendency to
believe the chassis lettering and schematic. The manual is internally
inconsistent, and doesn't agree with the physical hardware or
schematic. I probably can take out V5 and V11 and measure the
filament voltage present to see if it really is set up for a 6 or 12
volt tube in those sockets.
I found some correspondence between the original owner, whom I
purchased the unit from, and the factory regarding a technical
problem. The factory rep wasn't sure in solving a problem whether the
former owner needed a 6BZ6 or a 12BZ6 so he sent him one of each.
Apparently the factory didn't know either!
Was there some changeover for different serial number ranges, between
various tube types or what, and what is the best way to tell which
tubes really belong in the circuits?
Thanks for pointing me toward a resource, if you know one, to help
get some answers.
Phil WA2CLX
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