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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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22nd Oct 2017, 1:40 pm | #1 |
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Radiomobile 1170 speaker
I have a 1976 Radionmobile 1170 and would like to know what the speaker impedance and approximate wattage should be?
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22nd Oct 2017, 4:16 pm | #2 |
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Join Date: Mar 2006
Location: N.W. Oxfordshire(Chipping Norton)
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Re: Radiomobile 1170 speaker
As with most, if not all, car radios, the nominal speaker impedance is 4 ohms. IIRC, the audio power output of these was only about 6 or 7 watts maximum @ 14vDC supply, so almost any speaker which will fit where it needs to go, will be OK. There were two versions of the 1170, both with FM/MW/LW, one Mono, the other, designated 1170FMS, was stereo. Incidentally, IIRC, in the mid 70s, Radiomobile were still producing the 1070/1080/1085, & 1095. These used AD161/162 output transistors (The 1070, being single-ended, used an AD149), and had Blue top & bottom covers. THe 1170 came later in maybe the mid to late 80s.
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22nd Oct 2017, 9:07 pm | #3 |
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Re: Radiomobile 1170 speaker
thank you and thought it was a 70s radio oh well live with an 80s radio as it works and the condition very good. Service manual with circuit diagram would be good; any help appreciated.
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12th Dec 2017, 2:18 pm | #4 |
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Re: Radiomobile 1170 speaker
The radio I have only has MW and LW. I have the original 1170 product/guarantee card and the picture in here match the radio I have. The radio works although fades away after 5 minutes ish. Turn off for 10-15 minutes and it will come back on; so possibly a heat fault. I can try and isolate using a freezer spray although a circuit diagram could prove useful. Anybody have this or could assist as I am not getting very far with searching internet for a copy?
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12th Dec 2017, 5:27 pm | #5 |
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Re: Radiomobile 1170 speaker
I have just realised that I erroneously stated that the 1170 had FM in post #2. The 1190 and 1190FMS were the then top of the range models with VHF. Besides a PYE car radio, and a somewhat rare Motorola one, these were, AFAIK, the only UK Made FM car radios. That aside, the info. in the rest of post #2 is correct. It seems, JRW, that there is a fault in your 1170, possibly in the audio amplifier - a TDA2002 or 2003, IIRC. Despite working for a Radiomobile Dealer when this model was current, I don't recall ever seeing a circuit diagram or service manual for any of the 11xx series, although they were produced for all the preceding models.
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14th Dec 2017, 8:45 pm | #6 |
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Join Date: Jun 2017
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Re: Radiomobile 1170 speaker
thanks Livewire; are they standard output amplifier devices? Have freezer spray so will give that a go over xmas.
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14th Dec 2017, 11:40 pm | #7 |
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Re: Radiomobile 1170 speaker
The TDA2002 & 2003 are (or were) standard 5-pin audio amplifiers in a (TO-220?) Plastic package which looks like a power transistor with 5 pins. I haven't checked, but they may still be available from the likes of CPC, Cricklewood Electronics, etc., or from eBay sellers. I may even have one or more in my parts stock. I'll try and remember to look when next in my workshop. Blaupunkt and other manufacturers also used them 'back in the day'.
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15th Dec 2017, 12:18 am | #8 |
Dekatron
Join Date: May 2008
Location: Derby, UK.
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Re: Radiomobile 1170 speaker
All the TDA20xx devices are in electrically and dimensionally identical Pentawatt packages; and are just op-amps with non-inverting inputs, output and supply lines, optimised for low-impedance audio applications and capable of working close to the supply rails. The differences between them are just maximum ratings (voltage and current) and performance (max dV/dt, input current, internal impedance ......) so a lower-spec part can usually be replaced with a higher-rated part -- but watch out for bridged pairs, which should really be replaced as a pair of at least the same type number. Also beware of modern devices possibly having enough gain at ultrasonic frequencies to be susceptible to breaking into oscillation; you may need additional capacitors close to the IC.
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