I recently picked up a Realistic Lab-290 turntable where the previous owner replaced the 33/45rpm selector switch with what I think he thought was a power switch that just toggled 33rpm on and off?

I desoldered his switch and wired the old switch up, but I cannot find the location on the board for where the switch wires originally went.. I’ve looked everywhere online for a picture or diagram of the table but to no avail. There are some pictures but it uses what looks like an older board, I’ve tried multiple spots on the board but the only point I can get to work is where he soldered his switch which only turns 33rpm on and off. There is a switch on the board that if toggled changes it to 45rpm. But the original switch is a top hat that switches between 33 and 45rpm and I’d like to revert to that.

Could anyone help decipher where I should wire the original switch? I don’t wanna keep going on with trial and error and blow the components on it. I thought at first it should be before or after the VRs in place of R204 or the center rectangle where the paths lead, but that did not work.
Any help will be great!!
(Yes he used speaker wire to wire his switch

)

 

I can't find a schematic of that model, but many of the Radioshack turntables had a simple switch between two potentiometers that set the speed for each selection, similar to image below. Without better pictures that we can zoom into, hard to tell which tracks do what with your board. Follow the traces from those two potentiometers...

 

Can you point out where you think these wires are from, there is a changeover switch already on the board for speed selection??

 

I can't find a schematic of that model, but many of the Radioshack turntables had a simple switch between two potentiometers that set the speed for each selection, similar to image below. Without better pictures that we can zoom into, hard to tell which tracks do what with your board. Follow the traces from those two potentiometers...

View attachment 292003

I will take some better photos and draw a diagram because this is originally what I tried, the previous owner placed his switch in the bridge rectifier circuit of the board and that is the only location where I can get the original switch to work, but it does not work as intended. I will take some better photos and draw a schematic up and post a reply. Thanks, could you tell me what model that diagram you posted is from?

 

Can you point out where you think these wires are from, there is a changeover switch already on the board for speed selection??

That is what confuses me, when depressed the table spins in 45 rpm, and 33rpm when not. The pots all lead to that switch on the board but I cannot find where the wires go for the switch on top of the table to switch between the two. His switch was wired where the 2 orange leads are near the bottom right cap in the first picture, (that is along the bridge rectifier circuit.) I will post some better photos and draw a diagram. I will post a reply, thanks!

 

I can't find a schematic of that model, but many of the Radioshack turntables had a simple switch between two potentiometers that set the speed for each selection, similar to image below. Without better pictures that we can zoom into, hard to tell which tracks do what with your board. Follow the traces from those two potentiometers...

View attachment 292003

 

The terminals 4/5 bottom right of picture ( c202) are the on off switch terminals ( orange wires), this goes in series with the AC supply, is this what you are looking for?

 

I initially thought that the switch on the board was a DPDT swich but that does not make sense as the center connection on the side nearest the board edge would be common for one pole. as there is no connection to what would be the NC and NO connections. Can you meter out continuity between the switch connections for both positions of the switch. Can you show the switch that you are trying to connect to the board showing how many connections it has. What controls wheather the speed is set by the on board switch or the other switch ?
From what I have traced so far the motor is supplied with unregulated DC from the bridge rectifier and the electrolytic capacitor. (Red and black motor wires.) VR202 in series with an 18K resistor is connected between the brown and white motor wires. The speed change switch just seems to connect VR201 in parallel with VR202 and the 18K resistor.

Les.

 

The terminals 4/5 bottom right of picture ( c202) are the on off switch terminals ( orange wires), this goes in series with the AC supply, is this what you are looking for?

That is where the previous owner added his switch in location of C202, but this just is an on/off switch for 33rpm to change over to 45 I'd have to press in the white switch directly on the board. Then the switch is on/off for 45rpm, the original switch just cycled between the 2 not on and off. Would it be incorrect to add in jumper in place of C202 to keep the circuit active when the tonearm switch is engaged and remove the switch from the board and solder jumpers from the original 45/33 selector to the location on the board where the other switch is?

 

I initially thought that the switch on the board was a DPDT swich but that does not make sense as the center connection on the side nearest the board edge would be common for one pole. as there is no connection to what would be the NC and NO connections. Can you meter out continuity between the switch connections for both positions of the switch. Can you show the switch that you are trying to connect to the board showing how many connections it has. What controls wheather the speed is set by the on board switch or the other switch ?
From what I have traced so far the motor is supplied with unregulated DC from the bridge rectifier and the electrolytic capacitor. (Red and black motor wires.) VR202 in series with an 18K resistor is connected between the brown and white motor wires. The speed change switch just seems to connect VR201 in parallel with VR202 and the 18K resistor.

Les.

The first image is the switch that the previous owner installed. I have reinstalled it (at c202) because it’s the only way the complete the AC circuit (unless I could use a jumper?)
The second and third photos are the original switch designed to cycle between 33/45rpm. It seems to be exactly the same as the switch on the board.
The final 2 photos are something I tried last night. Keeping the switch previously installed left on, and installing the original switch to the center rectangle which has continuity with the switch. In the off position the table spun at 33rpm (this wire was to a common) however when engaged for 45rpm I believe it was sending a full 12v signal to the motor instead of cycling to 45 so I immediately knew this was wrong.
i stated in a reply above would it be incorrect to leave the switch (or a jumper?) from the old owner engaged leaving the circuit active as I believe intended (because the tonearm switch engages the transformer) and removing the switch on the board and soldering jumpers from the original switch to the location on the board where the white top switch currently is? It’s a thought I had however if it would be technically incorrect I don’t want to. As I’d like it to be as original as possible

 

I have been confused trying to understand why you seemed to want to have two switches to change the speed but after seeing th second and fourth pictures in post #10 I now assume the board was made to be used in a model where the on board switch was accesable to the user and on your model you just want to use the switch with the orange wires to change speed, This is possible but the on board switch MUST BE SET TO THE POSITON WHERE IT'S CONTACTS are OPEN. I will have to trace the tracks to find two unused through hole connections where you coul connect the orange wired in parallel with the on board switch contacts. Thow other options are to sojder the orange wires to the underside of the board directly to the on board switch connections. The other option is to remove the on board switch and connect the orange wires to two of the holes from where the switch was removed.

Les.

 

I have been confused trying to understand why you seemed to want to have two switches to change the speed but after seeing th second and fourth pictures in post #10 I now assume the board was made to be used in a model where the on board switch was accesable to the user and on your model you just want to use the switch with the orange wires to change speed, This is possible but the on board switch MUST BE SET TO THE POSITON WHERE IT'S CONTACTS are OPEN. I will have to trace the tracks to find two unused through hole connections where you coul connect the orange wired in parallel with the on board switch contacts. Thow other options are to sojder the orange wires to the underside of the board directly to the on board switch connections. The other option is to remove the on board switch and connect the orange wires to two of the holes from where the switch was removed.

Les.

Thank you for such a quick response!!! That would be great, I have been trying to find what contact on the board to connect the orange wires to but nothing has seemed to work. But exactly, I would like to just have one single switch (the factory one located on top of the table) that switches between the two speeds. I suppose if that doesnt work I will be removing the on-board switch and soldering directly to there but if there are holes in the board where it will work that would be awesome, however i cannot seem to find where they will work. I have also left the switch on the board open, I have also tested with it pressed in (closed)

 

I have uploaded a version of the etch side with numbers added to the onboard switch connections. (The red lines also show the wire links on the component side. The image is rotated and mirrored to make it easier to match it up woth the component side.


There is nowhere to connect to pin 4 of the switch from the component side of the board. You could unsolder the right hand orange wire from where it is now soldered and solder it to pin 4 of the onboard switch, I think that should do what you want, The onboard switch must be in the position where it DOES NOT show continuity between pins 4 and 5. To save taking the orange wire to the underside of the board you could bridge 2 to 4 on the switch with a shot piece of bare wrire and solder the orange wire to the other end of the track that commes from pin 2, The alternative is to remove the onboard switch and solder the orange wires to the pads 4 and 5 from where the switch was removed,

Les.

 

I have been confused trying to understand why you seemed to want to have two switches to change the speed but after seeing th second and fourth pictures in post #10 I now assume the board was made to be used in a model where the on board switch was accesable to the user and on your model you just want to use the switch with the orange wires to change speed, This is possible but the on board switch MUST BE SET TO THE POSITON WHERE IT'S CONTACTS are OPEN. I will have to trace the tracks to find two unused through hole connections where you coul connect the orange wired in parallel with the on board switch contacts. Thow other options are to sojder the orange wires to the underside of the board directly to the on board switch connections. The other option is to remove the on board switch and connect the orange wires to two of the holes from where the switch was removed.

Les.

I have uploaded a version of the etch side with numbers added to the onboard switch connections. (The red lines also show the wire links on the component side. The image is rotated and mirrored to make it easier to match it up woth the component side.
View attachment 292144

There is nowhere to connect to pin 4 of the switch from the component side of the board. You could unsolder the right hand orange wire from where it is now soldered and solder it to pin 4 of the onboard switch, I think that should do what you want, The onboard switch must be in the position where it DOES NOT show continuity between pins 4 and 5. To save taking the orange wire to the underside of the board you could bridge 2 to 4 on the switch with a shot piece of bare wrire and solder the orange wire to the other end of the track that commes from pin 2, The alternative is to remove the onboard switch and solder the orange wires to the pads 4 and 5 from where the switch was removed,

Les.

Can't thank you enough for taking the time to do this, I will try this shortly and get back to you!!!

 

I have uploaded a version of the etch side with numbers added to the onboard switch connections. (The red lines also show the wire links on the component side. The image is rotated and mirrored to make it easier to match it up woth the component side.
View attachment 292144

There is nowhere to connect to pin 4 of the switch from the component side of the board. You could unsolder the right hand orange wire from where it is now soldered and solder it to pin 4 of the onboard switch, I think that should do what you want, The onboard switch must be in the position where it DOES NOT show continuity between pins 4 and 5. To save taking the orange wire to the underside of the board you could bridge 2 to 4 on the switch with a shot piece of bare wrire and solder the orange wire to the other end of the track that commes from pin 2, The alternative is to remove the onboard switch and solder the orange wires to the pads 4 and 5 from where the switch was removed,

Les.

Hi Les,
So when I left the orange wire in the center hole, removed the right hand wire and soldered it directly to pin 4 just to test it for now. When I do this (with no continuity between pins 4 and 5) it just toggles 45rpm and off. I then removed the old owners switch that he installed (seen in picture 1 of post 10) the motor wouldnt turn on because the incomplete AC circuit.
I think at this point ill just remove the on board switch and wire directly to the through holes!

 

Can you confirm that the orange wire that is still soldered into the group 5 holes surounded by the white rectangle is in the middle hole of the 5. (I.E there are two empy holes either side of it.) With the onboard switch in the open position if you test continuity between 4 and 5 it should show continuity when the external switch (The one in the end of the orange wires.) is closed and no continuity when the external switch is in the open position. Which state of the onboard switch (open or close.) coresponds to 45 RPM ?

Les.

 

Can you confirm that the orange wire that is still soldered into the group 5 holes surounded by the white rectangle is in the middle hole of the 5. (I.E there are two empy holes either side of it.) With the onboard switch in the open position if you test continuity between 4 and 5 it should show continuity when the external switch (The one in the end of the orange wires.) is closed and no continuity when the external switch is in the open position. Which state of the onboard switch (open or close.) coresponds to 45 RPM ?

Les.

Yes, I left the one orange wire in the center hole of the 5 in the rectangle. With no continuity between pins 4 and 5 of the on board switch. The switch im trying to wire in did nothing, open and closed the motor remained in 33rpm state. With continuity between pins 4 and 5 the switch would act as a 45rpm on/off. I have just unsoldered the on-board switch out of frustration lol as I had already spent a few evenings after work attempting to make it function as normal before coming to the forum.
Could any of this have to do with the switch the old owner placed in location of C202??

 

I don't see how the switch connected in place of C202 can effect the speed. It just breaks the AC feed to the bridge rectifier. (It is just a power on / off switch) Can you confirm that there is continuity between the pads 5 and 6 even with the on board switch removed ? Can you confirm that there ar no connections to pads 1 and 3. (I can't see any tacks going to those pads in the pictures.) What happend if the orange wires are connected to pads 4 and 5 ? On the pad on the right hand end of the upper of the two red lines there looks like a solder spash shorting to the pad above it, Check if this is shorting the pads.

Les.

 

I don't see how the switch connected in place of C202 can effect the speed. It just breaks the AC feed to the bridge rectifier. (It is just a power on / off switch) Can you confirm that there is continuity between the pads 5 and 6 even with the on board switch removed ? Can you confirm that there ar no connections to pads 1 and 3. (I can't see any tacks going to those pads in the pictures.) What happend if the orange wires are connected to pads 4 and 5 ?

Les.

Okay, that is what I thought thanks for clarifying.
With the onboard switch removed and open there is no continuity between 5 and 6. When closed there is continuity. As for on the board itself, there is no continuity between pads 5 and 6. Only continuity between 4 and 5
There are absolutely no connections to pads 1 and 3 at all, no traces on the bottom and no jumpers or anything connected to them from the top.
I will first test connecting the orange wires to pads 4 and 5, if that does not work (i dont see why it wont?) I will go ahead and solder all 6 wires to the on-board switch holes to the switch with the orange wires.

 

I don't see how the switch connected in place of C202 can effect the speed. It just breaks the AC feed to the bridge rectifier. (It is just a power on / off switch) Can you confirm that there is continuity between the pads 5 and 6 even with the on board switch removed ? Can you confirm that there ar no connections to pads 1 and 3. (I can't see any tacks going to those pads in the pictures.) What happend if the orange wires are connected to pads 4 and 5 ? On the pad on the right hand end of the upper of the two red lines there looks like a solder spash shorting to the pad above it, Check if this is shorting the pads.

Les.

Hi Les,
So when the 2 orange wires are connected to just pads 4 and 5 it works! Just backwards.... the original switch is supposed to be 33 when open, and 45rpm when closed. but its 45rpm open, when I press the switch in it changes to 33rpm. So Close! Just opposite... I tried switching the wires on the switch itself around but that changed nothing... should i just go ahead and wire all 6 jumpers to the board? Thank you so much for your help!!!