|
|
Post by Straycatakis on Jan 30, 2018 22:45:55 GMT
Hello everybody,
My 2050 tube is missing on my jukebox. Of course it cannot trip the record because of that.
I would like to know does that tube affect the sound at all? When I trip by hand and it plays, the sound is distorted.
Can it have anything to do with the 2050 tube? I think not but am not absolute sure.
|
|
|
|
Post by Ron Rich on Jan 30, 2018 23:37:22 GMT
Ab-sol-lut-ly not ! I would humbly suggest that a copy of my "Seeburg Mechanism Guide" should be of help in understanding that jukebox ---contact me, if you wish to purchase it at: ronnnrich@yahoo.com Ron Rich
|
|
|
|
Post by Straycatakis on Jan 31, 2018 9:49:56 GMT
Hi Ron and thanks, I was pretty sure this has nothing to do with the amp but had to make the silly question! I have recapped everythin plus the TSU and I am wondering what can be going wrong. I believe it is either a bad cartridge or stylus, or the pot maybe? I have tested the speakers and work great.
|
|
|
|
Post by Ron Rich on Jan 31, 2018 14:27:57 GMT
Well, since you have failed to note the phono, or amp model, I can not offer any other suggestions--just a gut feeling--it's not the cart.--Ron Rich
|
|
|
|
Post by Straycatakis on Jan 31, 2018 17:38:48 GMT
Yes you are right, sorry for that. it is DS with shfa-5 amp and a TSU7. I will double check the amp again. Maybe a bad capacitor was purchased in the lot... I did a stupid thing not to check them one by one before placing. I have not replaced the resistors, so I will have to go through them too. Thanks again
|
|
|
|
Post by Ron Rich on Jan 31, 2018 17:57:30 GMT
EZ quick check-- pull the input and mute plug out -- turn volume to full --touch your finger to the input caps one at a time-- no "hum"-- Bad amp--connections to, or the speakers, themselves--Ron Rich
|
|
|
|
Post by Straycatakis on Jan 31, 2018 22:33:13 GMT
I will check and get back to you Ron. I was thinking of plugging in another turntable to check the amp. If I remember well it gives a loud HUM when the input plug is touched. Is it possible to check the cart also by plugging it in a phono-in plug on a stereo? My redhead cartridge reads about 560 ohms.
|
|
|
|
Post by robnyc on Feb 1, 2018 14:43:58 GMT
Hello Takis, we meet again...Yes, the approach is to sub another T-T/ magnetic cart and also try hooking up the Seeburg cart to your external amp. 560 Ohms is right within the range of those carts that I have measured (570-610 Ohms).
It is highly unlikely that the cart itself is at fault. Styli are the main suspects here.
An inoperative AGC will also cause distortion -especially on loud records. This is due to the nature of how analog gain control circuits work. Excessive gain is designed-in and the control circuit attenuates it as needed. Often, there is not much headroom and if the AGC does not work the following stages get overloaded.
That amp uses packaged selenium diodes to both generate the control voltage (CR102) and do the actual attenuation (CR 103- 104). Those should be replaced with silicon diodes as the old one lose control and both distortion and channel imbalance result. I use "whatever" low -medium voltage diodes on-hand. (1n4001-2-3 etc) Use two in series for each leg of the selenium diodes you are replacing. You'll be using 12 diodes in total and make sure you use the same type for each leg.
RobNYC
|
|
|
|
Post by Straycatakis on Feb 3, 2018 22:18:12 GMT
Hello Rob, again :-) I still haven't done any progress with the amp. I will go get a dozen of 1n4001 and follow your advice. I will get some t-needles from the States, but I will have to wait about one month to get them and find out if they are really to blame or not! I also suspect the 25.000 ohm resistor, that seems to get hot as hell (although seems to read well) that is odd!
My attention now is mostly on a tripping problem that looks weird. After placing the missing 2050 tube it still does not trip after scanning twice. I did the the A to B test and it trips immediately. So I suspected the 12ax7 tube, wich I replaced... but still nothing. (It might trip sometimes, lets say 1 in 20 attempts, but when I try again it doesn''t). I then thought of the tormat connection pins and cleaned them good, but still nothing. I am now thinking it might be out of align causing this problem... Anyway I will probably find out what is going on sooner or later, but just stuck for now. I might mention this on the fb Seeburg group too, to hear some suggestions there too! Sometimes it can be something really simple that just does not cross your mind.
Thank you for all the advise you gave me in the past and still are giving... I really appreciate that very much!
|
|
|
|
Post by robnyc on Feb 4, 2018 0:20:32 GMT
|
|
|
|
Post by Ron Rich on Feb 4, 2018 2:50:42 GMT
Takis,
Before wasting more time, you need to figure out if you have a write-in, or read out, problem--quickest way to do this is with a D cell "flashlight" battery. Pull out the RCA plug on the TPA. Place the D cell on bare metal--neg down, touch the pin of the RCA plug to the + side of the battery, Start the scan--mech should stop at EVERY space---- if this happens, your read-out section is working--
|
|
|
|
Post by Straycatakis on Feb 4, 2018 10:43:25 GMT
Ron I was talking about the 25k 10w resistor in the amp (shfa-5) under the capacitor can that gets VERY hot. That has to do with the amp repair. I want to change that too along with the diodes.
Now for the tripping problem... The cap in the pulse amp has been changed along with all the rest of the caps in the TSU.
The battery test does not work, but when I do the "L" test it trips (connecting A to B). Even if the battery test does not work I suspect a read out problem... that is because it does have tripped randomly 2-3 times during my tests. So I believe it does write in. I suspect after some thinking the read out switch on the back of the mech, next to the detent switch. I believe they usually go bad due to grease oil and stuff like that.
I will check with an ohm meter while turning the motor slowly by hand to see the results, and if it is aligned perfectly. (will check that today)
I also would like to ask you what exactly is the seeburg testing lamp? Will any 110v neon mini bulb do? maybe with a resistor soldered on?
|
|
|
|
Post by Ron Rich on Feb 4, 2018 15:02:29 GMT
Takis,
A 25 k 10 w resistor is supposed to run hot ! When ever you see either a square "sand-block" or a large "round/open style" resistor--keep your hands off as they WILL, remove skin ! You have a read-out (RO)/sense problem, if the battery trick won't cause it to trip(You also may have a write-in(WI) problem, but you need to get the RO problem fixed first, to test the WI) . This could be in the TSU, or the mechanism. Have you worked on the TSU ? All "lytics"/"paper", caps must be changed, and ALL resistors checked for value, first. After that, check the Detent, read-out switch, behind the motor--his MUST be free of oil/dirt,and correctly set as per the manual--pay particular attention to the "air gap". After that, remove the TMU. Clean all rivets with a safety solvent (NO abrasives !), and clean the silver center bar--then check all Phillips screws--these must be snug, but NOT over-tightened, as they are connected to Tinnerman nuts. Check the tops of the pin plungers--they must be flat, to slightly domed on top, and MUST still have silver on them--check/replace the wiring on each one--this is 32 gauge wire -- Two more things to check-- The soldering on the RCA plug on the TPA-1. There should be three "wires" soldered there. One to the tip, and a wire and the shield to the ring. Check alignment of the contact block ("frog") to the TMU--Use only enough upward pressure as needed on the frog !
That "Seeburg test lamp" was a NE 57 H, or eq in series with a 33k/1/2 watt resistor ( which will get hot when left on !)
|
|
|
|
Post by Straycatakis on Feb 6, 2018 20:12:48 GMT
So here is some feedback Ron and Rob... We were both right and the problem was in the RO. Cleaned the RO detent switch and properly adjusted it according to the book! I also found the 5.6 MΩ resistor in the pulse amp was open (I couldn't even read it with my meter), so as Rob suggested I changed it.
Some adjustment on the magazine record rack too and all is fine now with the mech. Works like a charm.
Now to solve the amp problem. I didnt find any 1N4001 diodes so I got some 1N4004... I asume it;s the same and it's no big deal, so I will use them.
I also am waiting for new stylus to arrive from your country :-) so lets see how that will go too.
There is one more problem I have to solve now, but I will start a new thread for that... it's about the credit system.
Thank you very much for all Ron and Rob, you were great help (once again).
Takis Z.
|
|
|
|
Post by robnyc on Feb 7, 2018 7:00:34 GMT
Well, speaking as the younger and (possibly) handsomer half of Ron & Rob, I am glad you got that up and running. The 5.6 meg is a common problem on the pulse amp.
!n4004 Should be fine. I use the smaller types simply for space and often the leads on larger diodes don't fit the tiny holes in boards. That won't be a problem on your amp.
RobNYC
|
|
