Hammarlund HQ 100A Communications Receiver Video #2 - Tubes Tested
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- čas přidán 6. 09. 2024
- It makes sense to test all the tubes in this radio before doing anything more. The 6BV8 tube is of particular concern because it is rare and the 6BE6 could be a Sylvania which can behave poorly in this particular radio according to a service bulletin. Since the radio operates, it's unlikely any of the tubes are bad but the possibly must be eliminated before more work is undertaken.
Impeach Gregg!
Put the 6bv8 tube in the radio and see if the filiment glows. I wouild just buy a tube, it's about only 8$.
the website he showed said they had it for 5$
The tube is certainly working. His tube tester is just partly broken like most of his test equipment is. The Weston tubechecker 981 rev 3 uses an Amperite Ballast Tube to regulate the current for the elusive 600mA series string heater setting. This ballast tube is probably burnt out.
The revision 4 model however does away with the ballast and uses a 5V tap on the xformer instead.
And to add insult to injury, 6BV8 is a misnomer anyway. If one sticks to the rule that the first numerical represents the heater voltage it should have been named 5BV8, because the heater voltage of this tube at 600mA is settling in at about 5V AC. (See timeindex 48:15 tube voltage chart for V7; 6,3VAC - 1,2VAC = 5,1VAC)
His problem with the receiver - if there is one - will most probably be bad couplets or drifted carbon comp resistors.
But since we hear him say that only tubes and caps are ever the cause of trouble, I have no hope of seeing this receiver properly fixed. Leave it to the diligent and conscientious repair people like Bob Anderson, David Tipton, Mr.Carlson, M.Caldeira et al to also check for out of spec resistors.
Realistic = Radio Shack
With RadioShack being known as "Tandy" in Europe and Australia
And as for that "Made in Japan" 12AX7/ECC83 tube there;
In the 70's as tube sales plummeted, Philips, who had previously bought up the tube mfc Mullard, decided to ship some of their old tooling for the production of vacuum tubes to Japan, which led to Matsushita (Panasonic) making tubes on old Mullard equipment.
Radio Shack who bought the cheapest tubes they could get rebranded them as Realistic lifetime.