Volvo radio model numbers have puzzled many people for a long time, but there is some logic behind it if you know about it! The following applies to "SC-" prefix radio numbering:
So for example, the SC-805, SC-815, SC-825 and SC-835 are essentially the same radio but have minor customisation for the European, American, Australian and Japanese markets respectively. The pics below show a UK spec SC-805 (grey face) and the equivalent Japanese SC-835 (black face). There are a few differences, but they're minor. In fact, I've swapped the face plates between these two radios so that I have the original black face of the SC-835 on the SC-805 radio to retain the OEM look:
The SC-816/836 may look very similar to SC-815/835 but under the skin there are a few minor differences:
Finally, the SC-900 and SC-901 have hidden menus to change the market configuration without the need for special hardware. The SC-901 also has a modified CD tray mechanism which is said to be more reliable than the earlier SC-900.
The SC-900 provides analog Dolby ProLogic Surround for the CD and Cassette sources only. The integral 3 disc changer is quite slow to operate, and has a reputation for being temperamental.
The "MODE" button toggles through three settings: (from Owners manual)
The SC-901 provides analog Dolby ProLogic Surround for all 3 input sources. The SC-901 integral disc changer is a revised version of the SC-900 mechanism, and is generally more reliable and quicker to operate than the earlier SC-900.
The "MODE" button toggles through three settings: (from Owners Manual)
The SC-901 also has a hidden menu with a seperate 5 band equaliser. To access this feature:
Adjust the setting by turning the Tune knob. The change can be seen in the display, as well as heard.
Use preset button 6 to adjust the settings of the front or rear speaker. Note that the equalizer curves can be adjusted separately for the front and rear speakers. When you are satisfied with the adjustments you have made, press Scan again to store the settings. Press Scan once again to exit the settings mode. To select your custom equaliser configuration, select "Custom EQ", press the Volume knob.
Some other hidden menu options are to set the market configuration - this is usually done by the original suppling dealership. To view/change this setting:
Another interesting and potentially useful feature is the ability to change the preset 'environment' - this is useful if you are fitting an SC-901 from a C70 into another vehicle such as an 850 estate:
Radio 'test' feature:
Most 1990s era Volvo radios have a 'test' mode which allows you to operate the radio for a few minutes without entering the security code. This means that the user can check that the radio, CD, tape etc works even if the code is not known/forgotten. Note that I believe that this only works for a few occasions, after which a code must be entered.
To power on the radio without using the security code :
The radio should power on for around 10 minutes before locking again.