Part of your problem there is that your standard 7493 (facts sheet here) needs to charge for 60 minutes before you can get anything from it.
Of course, I jest. BUT it is important to know which breed of 7493 you have. On my HCT variant, for example, pins 8, 9, 11 and 12 are OUTPUTS and I wouldn’t attach a PWM to them. It has no R pins (is this the same as HR?) There are different Vcc variants, too.
PWM? What’s PWM got to do with anything? Is that simply the mechanism to get the Ard-whine-oh to output a square wave pulse train? Did you try a 50% mark to space ratio?
Be aware, also, that some types are fussy and need their unused inputs tied to Vss or Vdd. (Probably irrelevant as you appear to be using input B to cascade the two counters.)
I can probably help if I know the flavour of the beast.
Same stuff Just as jka states, if you check page 6 of your datasheet, at least one of the RO(1) or RO(2) pins needs to be low for the counter to operate, and probably best to ground both. And if it is a 7493, then it’s a binary counter, the decade counter is part number 7490. The other connections you have sound fine.
slow the input clock to 7493 You slow your count down by slowing the input clock to the 7493. Sounds like you are driving it with a pwm counter timer, so you either increase the max count on the counter (which should slow the output clock) or slow the clock going into the pwm. If you are using the Arduino there is a programmable divider (prescaler) on the pwm clock input. I see it has divide by 8, 64, 256, and 1024 that you can use. But I’m too new to the Arduino to tell you how to do that exactly. Hopefully that points you in the right direction.
Apples and Oranges Are you sure the data sheet you uploaded is the corect one for your flavour of chip? Read me the part number from the top of the chip.
Frequency vs Ratio I think the chappies might be suggesting a slower FREQUENCY for you PWM rather than a lower mark to space ratio. I know NOTHING of picaxe, but I know my PWM from my square wave… Definitely roll with 50% PWM, but reduce the frequency.