|
Hi to all in the group! While having not fully finished repair work on the low-serial TR7 I posted about some while ago, an opportunity came up this weekend that I just could not turn down - a Drake TR4310 (HF) Communications Transceiver. When will I learn to finish one project prior to starting the next! The example I have acquired (2xx serial number) started life in Africa. Retired from commercial service, it was gifted to a UK amateur who happened to be passing through the country in the course of his employment. He sold it to me for a most agreeable price, in view of it having been in storage for some years, now not working and with some UK repair shop hinting it would be uneconomic to put right. The transceiver is dirty, but in good physical shape. It came with the full, paper service manual, which documents all of the differences between the TR4310 and TR7, on which it is firmly based. The parent board in it is stamped '5 May 1981', so around the time Drake was transitioning between making TR7 and TR7A. I've had the radio on the bench this afternoon. Annoyingly, I cannot find the small Allen key that will allow me to take the knob off the bandswitch (anyone know the size of this?). As a result, I am unable to hinge the front panel down and pull the display board and get to the boards underneath. I pulled all of the boards in the top-rear card cage and have cleaned all their Molex connectors, plus the relay contacts. The 4310 has all four filter slots filled as standard:-) Looks like there is an AUX7 board fitted, with maybe some band modules too:-) With no short circuit on the power input connector and internal fuse intact, I connected up an antenna and applied power. Sure enough it didn't work. Well, actually, quite a lot of it did! I have all voltage rails coming out of the power supply. The display has a few digits lit. Audio and RF gain controls are good. Mode, Filter and PBT functions change the noise in the speaker in the way you would expect. The calibrator produces drifty audio tones in the loudspeaker. Switching between bands and turning the Aux Program knob causes the 'set band' to illuminate and extinguish. On the negative side, there's no MHz digits displayed on the seven segment LED frequency readout for any band. Turning the knob on the (synthesised - yeah, like an RV75!) internal VFO causes some change to the last three right-hand digits, but does not look correct. I think the number one issue is lack of VHF local oscillator injection. I plugged in an RV7 external VFO and got no better results. I'm looking forward to getting this one going and will post updates to this thread once I get further down the line. One thing I am already enjoying is how much easier it seems to be to get to everything in the radio, compared to a TR7, especially the RF HPF and LPF assemblies (hope I will not have cause to go there). Should any other 4310 owners wish to chip in and share their experiences, please feel free. Regards, Mark.
|
|
TR-4: Three Questions Regarding Voltage Chart
1. Are the RECEIVE/TRANSMIT voltages shown for V5 reversed? When I was checking those in RECEIVE, I was getting the voltage values for the TRANSMIT values shown so I was wondering if those are upside-down. 2. Is the voltage for V14 pin 9 correct for RECEIVE? I'm getting 180v on that pin during RECEIVE. As stated in the paragraph below the chart, I'm using X-AM to check that tube's voltages. 3. V19 pin 9 shows "T.P." in that column. Is that a typo? The only thing I can think of for "T.P." here is Test Point and there's not one there (V1 pin 2 is the only official Test Point that I'm aware of in the radio). Thanks, Barry - N4BUQ
|
|
I had a TR7 about 15 years ago and loved it but I sold it to help finance my K3 purchase, which I also love and still have. I acquired a TR7 today from an estate today with the PS7. It's S/N 2713. The thing was pretty dirty and will need a case repainting but seemed OK otherwise and the price was right. Here's what I have gleaned so far: 1. The PS7 doesn't work. I hear the transformer thunk when I turn on the rig and the fans on the PS and TR7 both come on but nothing else. The fuse is good and not blowing so I'll need to fix that at some point. 2. The rig came on fine with a different PS and seems to RX and TX fine but power out was around 170 watts and the ALC light was not coming on. I adjusted the control on the ALC board to about 150 watts on 20M at full drive and the ALC light now works but stays on no matter how low I adjust the drive. I know there's another adjustment for that on 10M on a diffferent board but I haven't gotten to that yet. Power doers adjust down to zero now. 3. The S-meter reads very low but signals sound fine so guess that's another adjustement I need to make. Forward and reflected hardly move the meter and adjusting the controls by the antenna socket make no difference. 4. Some good news is that all 4 filter slots are full which is great news for a CW op like me. 5. There's a big change in noise between USB and LSB looks like carrier balance is off. 6. The sidetone volume level is very low, I have to turn the volume control way up to hear it. I do have a PDF copy of the service manual. The big question is will I need the board extenders to fix all this and properly align the rig? If so wheer can I find some that won't cost me too much? My apologies in advance for the many stupid questions I'm sure I will ask as this project moves foward! 73, Bill NZ0T
|
|
6EA8 - Brand Recommendations?
23
Still trying to troubleshoot my TR-4. I started checking the tube voltages and found a very weak 6EA8. I was getting about -1.7v at the test point so I tried swapping V1 and V3. That resulted in the test point dropping to about -0.5v. The Hickok 752A also showed the triode being only slightly above the minimum for that tube so I'm thinking of getting a pair where both halves of both tubes will be strong. Any recommendations on brands? Mine are RCA and I suspect that should be a good brand for them but I also figure that brand may not be as critical as for, say, the PA tubes. Thanks, Barry - N4BUQ
|
|
Band Switch
2
I am in need of a fully functional BANDSWITCH for a Drake L-4B. Any thoughts or anyone? Thank you Vince N8MQV
|
|
Looking for Help Understanding Hickok Testing Data
11
This is slightly OT but maybe not too much since it's related to the problems I'm having with my TR-4's 6EA8s. Looking at the datasheet for transconductance for a 6EA8: PENTODE: 6400 uMhos TRIODE: 8500 uMhos For my 752A, the settings are defined as: MULTIPLIER MIN TRANSCONDUCTANCE VALUE PENTODE X4 550 (550 x 4 = 2200) TRIODE X10 525 (525 x 10 = 5250) If that's all correct, then I'm not following why the pentode's minimum value is 34% (2200/6400) of the datasheet's value while the triode's minimum value is 62% (5250/8500) of the datasheet's value. Am I misinterpreting something? I would think that the minimum values are expected to be some percentage of the value in the datasheet (presumably based on a new, properly-functioning tube) but since they're apparently inconsistent then I'm confused. Can anyone help explain that? Thanks again, Barry - N4BUQ Thanks, Barry - N4BUQ
|
|
Drake K4OAH manuals
8
Does anyone know if Carol (K4OAH's wife) of Drake Service Supplement CDs is still selling the pdf or CD service supplements of Drake gear? I've purchased pdf files recently for my Drake 2B receiver. The other day I followed the website instructions and purchased a TR4/TR4C service manual. Normally Carol's fast return with a download link once payment is made. However, I haven't heard from her in the past 24 hours which is unusual. The following link is the website that sells those CDs or pdf file copies. R L Drake Service supplement CDs and PDF files 73 Mike W5RKL https://www.w5rkl.com
|
|
T-4X RF cage needed
2
Yes I think I have one but at moment I'm in a hospital and I may out next week so my address is OK on QRZ Call sign M0PAM MARTINS
|
|
SPR-4 AF control
4
It is a fact that on the TR7 a minimum of audio is heard when the AF control is turned fully down. On my SPR-4 the minimum level of audio is more than just acceptable, so I wonder if there is a remedy to the problem or a thing one has to live with. I lifted the leads to the AF control and checked the pot with an ohmmeter. 49 to 3909 ohms from the wiper to one leg, 3793 to 30 ohms to the other leg. Peter OZ8CTH
|
|
Functioning of the FR-4 frequency readout
Drakesters: I recently purchased a C Line that came with an FR-4 digital readout, complete with a manual that matches the serial number. I haven't taken the covers off yet but plugged it in and got an accurate frequency readout straight away. There are a couple of issues that I can't remember from the last one that I owned that I sold in around 1989: The SPDT switch in the back is supposed to either give the frequency of the Drake radio based on the frequency of the INJ signal available at either INJ connector round the back of the tx/rx. The switch on this one does not change to direct frequency readout and I was wondering if any of you who have owned one of these can refresh my memory as to whether this feature is supposed to work or was a change implemented after the manual was written. I do remember the INJ signal being touchy whenever something is "hung-off" the INJ signal. I bought a cheap Y cable with a RCA male going to two RCA female connectors and it looks to be of decent quality and is superior to the connector I had in the 80s, which was simply some short wires connecting "flying" female connectors off the single male connector. I have great results getting the readout to indicate the frequency ON RECEIVE but I lose the accurate frequency when I transmit and the readout goes to some strange frequencies like around 9 MHz or 11 MHz. Can any of you recall if the readout would wander during transmit? It doesn't seem that it should. I now am using the Y cable and a short Drake "ANT" cable that used to be used with a 2m transmit convertor. TIA. Steve Wedge, W1ES Time flies like an arrow. Fruit flies like a banana. Sent with Proton Mail secure email.
|
|
TR-3
4
Hello everyone, after some late evenings after work, I finally have my TR-3 up and running. Did make a few contacts on 80m using the EV 638 microphone with good audio reports. As being new to the TR-3 is it normal for 40m to be in ssb X position or do I have a problem? Thanks Tony N5DIM
|
|
I'm working on bringing a Drake TR3 back to life. During power up I noticed smoke coming from below the chassis. I quickly powered the TR3 off. I turned the TR3 upside down, front panel facing me, and found a 1/2W resistor that had overheated. The picture below shows the location of this resistor. Does anyone know the resistor's value and where on the schematic it's located? The Yellow shaft is used as a pointer and the Black arrow is also pointing to the resistor. It's to the "Left" of the audio transformer and between the 2 small PC boards. I need to determine what that resistor is so I can find it on the TR3 schematic then track down what caused it to over heat. The TR3 was in "receive" when the resistor overheated. There was no audio heard in the speaker. The 8 pin remote VFO plug was in place with pin 2 connected to pin 8 as shown on the TR3 schematic (the RV3 was not plugged into the remote VFO socket). Any help would be appreciated. Please reply direct to my email address. 73 Mike W5RKL https://www.w5rkl.com
|
|
items listed previously for sale
The Hastings hotsticks, Jackite windsock pole, and isolation transformer have been spoken for. Still have the Heath SB-200 and some of the other items in the QTH ad. 73, Evan, K9SQG
|
|
Possible Source of resstor overheating
2
Morning Bill, I did a few more resistance measurements this morning. After earlier measuring continuity from both sides of the resistor, one lead of the resistor to pin 11 on the rear power connector and the other lead of the resistor to the 60ufd 250VDC can capacitor and found continuity I then performed a few more measurements. First I measured the resistance from the junction of R111 and C145B to the plate of V16 through R90 220K to pin 5. I see R90 is 218K. The resistor is well within the 10% tolerance. Second I measured the resistance from the junction of R111 and C145B to V18 through R97 330K to pin 1. I see 328K. The resistor is well within the 10% tolerance. Third I measured the resistance from the junction of R111 and C145B to V18 through R99 330K to pin 6. I see 324K. The resistor is well within the 10% tolerance. The above measurements clearly indicate the overheated resistor is R111. I now need to order the TR3 capacitor kit from Hayseedhamfest.com. 73 Mike W5RKL https://www.w5rkl.com On 5/2/25 4:10 AM, Mike wrote:
|
|
Resistor R111 and C145B
2
I've done some additional wire tracing and I believe I may have found the overheated resistor on the TR3 schematic. From my wire tracing in the TR3, Pin 11 on the rear power connector is the +250VDC power supply voltage. Pin 11 connects to R111. R111 connects to the positive terminal of C145B, 60ufd 250VDC capacitor, one of the 2 capacitors in the only can capacitor in the TR3. I've found a picture of the underside of a TR3 and the color band of the overheated resistor are ORANGE ORANGE RED SILVER which is 3.3K 10% and it's a 1/2W resistor. If C145B shorts to ground under voltage then that could cause R111, 3.3K 1/2W resistor to overheat. This would short out the +250VDC rail causing loss of receiver function, no audio, etc. If my Ohms Law math is correct, a shorted C145B would cause 75ma of current to flow through R111 at a power level of 18W. I = E / R "E" is 250 "R" is 3300 250 / 3300 = 0.075 amps (75ma) 0.075 x 0.075 x 3300 = 18W I have measured continuity from one lead of the overheated resistor to pin 11 on the rear power connector and see continuity. I measured continuity from the other overheated resistor lead to C145B and found continuity. Using an ohm meter doesn't show C145B shorted but that's because the battery voltage is too low to measure the short in C145B. Under +250VDC C145B could easily short causing R111 to overheat and loss of +250VDC voltage to other circuits. I have a few more measurements to take to be sure then I'll have to replace C145 can capacitor. 73 Mike W5RKL https://www.w5rkl.com
|
|
Drake FF-1
I've seen this in the TR-4 manual but I don't think I've ever seen one: https://www.ebay.com/itm/314218762222 Thanks, Barry - N4BUQ
|
|
R7 Multi-Vibrator Harmonics
3
My R7 is working well, it seems. I am now running it on DC voltage. The multi-vibrator runs at about 28khz after it has been running for a while. It starts at about 24 khz when the R7 is first turned on. With no antenna connected I can still hear the harmonics drift across a frequency on 40M. I don't notice them with an antenna connected. And of course, they get stronger as you go to the lower bands. Is this normal? Dan (W3DF)
|
|
I went through the tune up procedure and everything looked good until I got to the last step and the plate current never goes above .1 on the plate meter. I have set the bias with the PS per the manual. I checked continuity on the relay (both TX/RX) - it was good on both tests and I see it engage on transmit. The system receives quite well - especially after tune up. Looking at the bottom it looks like all the electrolytic capacitors were replaced. The large electrolytic multi section was replaced by three capacitors under the chassis. All tubes test good. At this point I am stumped - unable to get any power out of it. One other odd thing - if you turn the TX gain up past about three ticks while receiving you can hear an oscillation tone. I have lots of test gear and have restored several other tube transceivers, receivers and transmitters so this is not my first "radio" LOL. TIA and 73's Don W. KD4APP https://kd4app.blogspot.com
|
|
Items sold from posting
Fellow Drake Enthusiasts, The D-104 Final Edition microphone and the Shure 450 version II have been spoken for from the list I posted on the reflector and the QTH.com ad. The other items are still available. 73, Evan, K9SQG
|
|
Interesting post on setting TR7 8.05 oscillator.
Found this on zerobeat under Drake Mods by VE3EFJ: 8.05 MHz Osc Won't Net This oscillator is varicap controlled and is used in conjunction with the 13.995 fixed oscillator to develop the BFO. In doing it this way, there is little chance that there will be BFO leakage, or what leakage there is, can be controlled. There is a trimmer adjustment to net the 8.05 MHz crystal, but what the manual fails to tell you is that this adjustment is also affected by the trim pots for the injection frequencies for the BFO. If you try to set this trimmer up and it just won't trim, try an arbitrary setting of the trimmer screw and see if, say, on LSB you can get it to the proper frequency with the trim pot for that mode. Would this actually work? If the best one can net the crystal is say around 5.646 instead of 5.645 will the rig work correctly if the trim pots on the power supply board for USB, LSB, CW, RTTY and AM will all adjust to the proper frequencies? Seems a lot easier than trial and error padding of C1029. 73, Bill NZ0T
|
Image Name
Sat 8:39am
Sat 8:39am