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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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15th Jan 2016, 2:39 am | #1 |
Tetrode
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Selena Vega B215 Circuit Diagram / Schematic
Hi, would anyone have a copy of the Selena Vega B215 circuit diagram? I found another thread with a three-part scan of the B216 but the components, component numbering and layout are quite different around the power supply section for example, which is where my problem lies.
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15th Jan 2016, 2:25 pm | #2 |
Heptode
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Re: Selena Vega B215 Circuit Diagram / Schematic
Are you sure that you have the correct model number?
The circuit diagrams that I have for these radios seem to suggest that the B215 and B216 radios are identical, save for the different bands covered. There is a table on the left side of the schematics listing the model numbers and the bands covered. However, those Selena radios have different incarnations! They are very similar to each-other, but the circuitry (and the boards) differ slightly. The B210-11-12 radios use Ge transistors, the B215-16-17 radios use mostly Si transistors, and there are also the B206-7-8-9 radios that is again a bit different (it also uses Ge transistors). The radios also came under different names, depending on the market they were sold. I do have the schematics for the different radios, so if you figure the correct model, I can probably help. Peter Last edited by orbanp1; 15th Jan 2016 at 2:39 pm. |
15th Jan 2016, 3:04 pm | #3 |
Dekatron
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Re: Selena Vega B215 Circuit Diagram / Schematic
Some poking about suggested that the Okean 214 is the same as B215.
Have a look at attached:
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15th Jan 2016, 4:27 pm | #4 |
Rest in Peace
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Re: Selena Vega B215 Circuit Diagram / Schematic
Hi Chris
Well done for finding it, but that has to be the absolute worst schematic diagram ever made, for someone to follow. Mike |
15th Jan 2016, 4:48 pm | #5 |
Dekatron
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Re: Selena Vega B215 Circuit Diagram / Schematic
Having looked at it, I'm inclined to agree. The PSU bit in bottom right and the FM Head top left aren't too bad but the bus and wire number interconnections make the rest a nightmare. Shades of modern digital circuits
Not too bad if an electronic component has failed but if a few wires need to be traced. Google found it- via a comment on a Scandinavian forum pointing at the Okean and a Romanian forum with the schematic!
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15th Jan 2016, 5:10 pm | #6 |
Nonode
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Re: Selena Vega B215 Circuit Diagram / Schematic
Daunting to look at at first but that sort of representation is common on industrial control circuits (crane controls are a typical example) and if I remember correctly certain Philips manuals.
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Brian |
15th Jan 2016, 8:29 pm | #7 |
Tetrode
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Re: Selena Vega B215 Circuit Diagram / Schematic
Thanks for your replies.
The OKEAN 214 circuit seems closer to both my 215s, but it's certainly not identical. Please take a look at the attached photos. I've got 22V AC coming of the transformer, which goes happily through the bridge rectifier. However, when it reaches "VT2" or "V2" depending on what schematic you are looking at the voltage dies off the right leg of what, according to the schematics, should be a KT961B. I guess these are equivalents but on my two 215s the transistors in place are 5BA7 and KT817A respectively. Furthermore R21, which you can see in both photos are 1.5K and seem to correspond to R20 in the schematic, which shows the value as 480 Ohms. Also neither one of my 215s has C20, which is shown in the 3-part schematic, but not in the OKEAN 214. The biggest puzzler for me is the orange, three-legged component in the corner of the heatsink to which the transistors right leg feeds. Anyone know what it is? It's not shown on either of the diagrams as far as I can see. Mine has 63A7 (with an odd shaped 6, perhaps the "Ѣ" Cyrillic character) or possibly upside down Є9. Anyone know what it is? |
15th Jan 2016, 8:39 pm | #8 |
Octode
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Re: Selena Vega B215 Circuit Diagram / Schematic
It is probably the transistor that is the error amplifier for the stabilised PSU, connecting to the base of the series pass transistor.
Ron |
15th Jan 2016, 9:31 pm | #9 |
Dekatron
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Re: Selena Vega B215 Circuit Diagram / Schematic
Well, it has a "V" designation like the other transistor and three leads, so it certainly is likely to be a transistor. I can see a resistor ..... If there was a Zener diode hiding around the back of that heatsink, that might convince me it was as Ron said.
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15th Jan 2016, 10:14 pm | #10 |
Heptode
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Re: Selena Vega B215 Circuit Diagram / Schematic
Looks like there are differences even between the B216s!
Here is a Russian/English schematics where components in the PS match what you have in your radio: http://www.radiohistoria.sk/Oldradio.../Selena216.pdf Just curious, is the mains voltage set correctly in your radio? My guess would be that it is not! That 22V AC from the transformer looks awfully high! That would give about 30V DC unloaded/unregulated voltage! The regulated output is only 8.5V according to the schematics! Check if the transformer is indeed wired for 220V! You could replace V18 (that orange transistor) with any "jelly-bean" Si-NPN transistor, like 2N3904, 2N2222, e.t.c., V2 with BD135-137-139 or similar. Do check the leads, the lead order of the Russian V18 (KT315B) is different from that of the 2N transistors. You could also replace the Zener to a 10.5V component or similar, then you would get more than the 8.5V presently. Good luck, Peter Last edited by orbanp1; 15th Jan 2016 at 10:41 pm. |
16th Jan 2016, 12:14 am | #11 |
Heptode
Join Date: Nov 2009
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Re: Selena Vega B215 Circuit Diagram / Schematic
Just to continue the thought process that the unregulated supply voltage is about 30V.
The Zener diode, D814V, is a 10V 340mW device. R20, the dropper resistor for the Zener is 470 Ohm, and there is 30V - 10V = 20V across the dropper resistor. It is about 42.5mA current, there is not much taken away by the base current of V18. That current through the Zener, with 10V on it, would dissipate about 425mW, and that is above the limit that is given in the spec for that Zener. So do check the Zener, and you could also increase the value of R20. Peter |
16th Jan 2016, 8:35 am | #12 |
Rest in Peace
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Re: Selena Vega B215 Circuit Diagram / Schematic
As hinted by Peter, I would also check the mains transformer primaries are wired in series, for 220v AC. The schematic shows 13.2v on transformer secondary.
Excellent job on finding the circuit, Peter. Mike |
18th Jan 2016, 9:42 pm | #13 |
Tetrode
Join Date: Nov 2011
Location: London, UK.
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Re: Selena Vega B215 Circuit Diagram / Schematic
Thank you so much for all your informative replies. I traced the fault to the orange transistor and have verified this by swapping in the transistor from the working radio. Could someone advise on whether whether or not a 2N3707 would work as a substitute for the orange transistor? It's the only NPN 2N transistor I have in my spares box at present.
By the way, I mistakenly stated the mains transformer was kicking out 22V AC but it is in fact around 17.6-8V AC. However, the DC voltage at the output of the bridge rectifier is 22V. The primary's inner two tags are linked on my broken radio but not on the working radio. I guess it must be configured okay though since the output is similar on both radios. |
19th Jan 2016, 1:16 pm | #14 |
Heptode
Join Date: Nov 2009
Location: London, Ontario, Canada
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Re: Selena Vega B215 Circuit Diagram / Schematic
The 2N3707 is fine as replacement, it is a 30V 200mA Si-NPN transistor.
The pin order is ECB when looking at the flat face of the transistor. Here is a datasheet: http://www.datasheetarchive.com/dl/S...s-00127082.pdf Regards, Peter Last edited by orbanp1; 19th Jan 2016 at 1:27 pm. |
19th Jan 2016, 5:56 pm | #15 |
Tetrode
Join Date: Nov 2011
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Re: Selena Vega B215 Circuit Diagram / Schematic
Thank you very much, Peter. That has worked nicely and brought the PSU and the radio back to life.
The schematic looks a very good match if not spot on for my radios! Much obliged to you for digging it out. Just discovered FM is not working now! I presume there's a post on remedial action for that somewhere but will it apply to my radio particular radio? Do you or anyone have any pointers on that before I go hunting. Thanks again to everyone who contributed to this post. Much appreciated and learned. |
19th Jan 2016, 7:02 pm | #16 |
Dekatron
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Re: Selena Vega B215 Circuit Diagram / Schematic
Check for local oscillator operation with another set tuned to a weak signal somewhere up the top end of the band and placed up against the Selena. If the Selena's LO is working, the other set will go quiet when the Selena is tuned 10.7 MHz below the station it is picking up.
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19th Jan 2016, 7:57 pm | #17 |
Tetrode
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Re: Selena Vega B215 Circuit Diagram / Schematic
Thanks Julie. I tried that and there is no effect on the working radio. I've turned up the volume on the FM band on the broken radio and there's nothing other than a little amplifier hiss right across the band.
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20th Jan 2016, 12:32 am | #18 |
Tetrode
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Location: London, UK.
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Re: Selena Vega B215 Circuit Diagram / Schematic
Okay, I checked the voltages stated in the schematic against the faulty FM radio and the working one. The voltages between the working and non-working radios are comparable but differ with the schematic's voltages. Reading previous posts there's mention of Ge diodes and caps in the discriminator and bandpass filter sections respectively; however, it looks like these apply to earlier models?
Here they are: Faulty FM.......Working FM .....V1................V1 E - 3.4V........E - 3.4V B - 2.7V........B - 2.7V C - 0.1V........C - 0.1V ....V2.................V2 E - 0.9V.........E - 0.9V B - 1.5V.........B - 1.2V C - 2.7V.........C - 2.4V ....V3.................V3 E - 3.1V.........E - 3.1V B - 2.4V.........B - 2.5V C - 0V............C- 0V Schematic Voltages: ....V1..... E - 1.05V B - 1.7V C - 3.45V ....V2..... E - 0.7V B - 1.3V C - 2.2V ....V3..... E - 1.3V B - 1.9V C - 3.8V |
21st Jan 2016, 1:45 pm | #19 |
Tetrode
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Re: Selena Vega B215 Circuit Diagram / Schematic
Any thoughts of where the fault might lie folks?
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21st Jan 2016, 2:27 pm | #20 |
Heptode
Join Date: Nov 2009
Location: London, Ontario, Canada
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Re: Selena Vega B215 Circuit Diagram / Schematic
A couple of points.
Looks like you did not measure the voltages with reference to the ground, that is the reason for the deviation from the voltages in the schematics. It also looks like that some of the leads at the measurement of V3 are mixed up (E - B). But that is just about the measurement, and the fact that the voltages are similar to the voltages in the working radio means that the transistors and resistors are probably fine in the non working radio. There is the possibility that the B215 on FM works with low-side injection, meaning that the oscillator frequency is below by 10.7MHz from the received frequency. So tune the not working radio e.g. to 108MHz, and try to listen to the oscillator signal with the other radio around 108 - 10.7 = 97.3MHz. Check at other frequencies as well. Also check the voltages on the transistors in the "RF AMP - IF UNIT" too. Make sure you use the ground as reference! You could also inject the IF signal from the FM tuner from one radio to the IF-UNIT of the other radio to see which section is not working. It would be the points 4 and 5 in the FM tuner, also marked as wires 24 and 23 (point 4 or wire 24 is ground, point 5 or wire 23 is the IF-signal). Disconnect wire 23 and bring in the signal from the other radio to the disconnected wire. Also join the grounds of the two radios together. Peter Last edited by orbanp1; 21st Jan 2016 at 2:33 pm. |